Format code with Blackdeepsource-transform-b65b5545

1 files changed, 1332 insertions, 496 deletions

diff --git a/plip/structure/preparation.py b/plip/structure/preparation.py
index 6b63d63..6b4f04d 100644
--- a/plip/structure/preparation.py
+++ b/plip/structure/preparation.py
@@ -10,12 +10,39 @@ from openbabel import pybel
 
 from plip.basic import config, logger
 from plip.basic.supplemental import centroid, tilde_expansion, tmpfile, classify_by_name
-from plip.basic.supplemental import cluster_doubles, is_lig, normalize_vector, vector, ring_is_planar
-from plip.basic.supplemental import extract_pdbid, read_pdb, create_folder_if_not_exists, canonicalize
+from plip.basic.supplemental import (
+    cluster_doubles,
+    is_lig,
+    normalize_vector,
+    vector,
+    ring_is_planar,
+)
+from plip.basic.supplemental import (
+    extract_pdbid,
+    read_pdb,
+    create_folder_if_not_exists,
+    canonicalize,
+)
 from plip.basic.supplemental import read, nucleotide_linkage, sort_members_by_importance
-from plip.basic.supplemental import whichchain, whichrestype, whichresnumber, euclidean3d, int32_to_negative
-from plip.structure.detection import halogen, pication, water_bridges, metal_complexation
-from plip.structure.detection import hydrophobic_interactions, pistacking, hbonds, saltbridge
+from plip.basic.supplemental import (
+    whichchain,
+    whichrestype,
+    whichresnumber,
+    euclidean3d,
+    int32_to_negative,
+)
+from plip.structure.detection import (
+    halogen,
+    pication,
+    water_bridges,
+    metal_complexation,
+)
+from plip.structure.detection import (
+    hydrophobic_interactions,
+    pistacking,
+    hbonds,
+    saltbridge,
+)
 
 logger = logger.get_logger()
 
@@ -25,8 +52,16 @@ class PDBParser:
         self.as_string = as_string
         self.pdbpath = pdbpath
         self.num_fixed_lines = 0
-        self.covlinkage = namedtuple("covlinkage", "id1 chain1 pos1 conf1 id2 chain2 pos2 conf2")
-        self.proteinmap, self.modres, self.covalent, self.altconformations, self.corrected_pdb = self.parse_pdb()
+        self.covlinkage = namedtuple(
+            "covlinkage", "id1 chain1 pos1 conf1 id2 chain2 pos2 conf2"
+        )
+        (
+            self.proteinmap,
+            self.modres,
+            self.covalent,
+            self.altconformations,
+            self.corrected_pdb,
+        ) = self.parse_pdb()
 
     def parse_pdb(self):
         """Extracts additional information from PDB files.
@@ -38,7 +73,9 @@ class PDBParser:
         IV. Alternative conformations
         """
         if self.as_string:
-            fil = self.pdbpath.rstrip('\n').split('\n')  # Removing trailing newline character
+            fil = self.pdbpath.rstrip("\n").split(
+                "\n"
+            )  # Removing trailing newline character
         else:
             f = read(self.pdbpath)
             fil = f.readlines()
@@ -57,19 +94,23 @@ class PDBParser:
                 lastnum = 0  # Atom numbering (has to be consecutive)
                 other_models = False
                 for line in fil:
-                    if not other_models:  # Only consider the first model in an NRM structure
+                    if (
+                        not other_models
+                    ):  # Only consider the first model in an NRM structure
                         corrected_line, newnum = self.fix_pdbline(line, lastnum)
                         if corrected_line is not None:
-                            if corrected_line.startswith('MODEL'):
+                            if corrected_line.startswith("MODEL"):
                                 try:  # Get number of MODEL (1,2,3)
                                     model_num = int(corrected_line[10:14])
                                     if model_num > 1:  # MODEL 2,3,4 etc.
                                         other_models = True
                                 except ValueError:
-                                    logger.debug(f'ignoring invalid MODEL entry: {corrected_line}')
+                                    logger.debug(
+                                        f"ignoring invalid MODEL entry: {corrected_line}"
+                                    )
                             corrected_lines.append(corrected_line)
                             lastnum = newnum
-                corrected_pdb = ''.join(corrected_lines)
+                corrected_pdb = "".join(corrected_lines)
             else:
                 corrected_pdb = self.pdbpath
                 corrected_lines = fil
@@ -81,8 +122,8 @@ class PDBParser:
             if line.startswith(("ATOM", "HETATM")):
                 # Retrieve alternate conformations
                 atomid, location = int(line[6:11]), line[16]
-                location = 'A' if location == ' ' else location
-                if location != 'A':
+                location = "A" if location == " " else location
+                if location != "A":
                     alt.append(atomid)
 
                 if not previous_ter:
@@ -107,12 +148,18 @@ class PDBParser:
     def fix_pdbline(self, pdbline, lastnum):
         """Fix a PDB line if information is missing."""
         pdbqt_conversion = {
-            "HD": "H", "HS": "H", "NA": "N",
-            "NS": "N", "OA": "O", "OS": "O", "SA": "S"}
+            "HD": "H",
+            "HS": "H",
+            "NA": "N",
+            "NS": "N",
+            "OA": "O",
+            "OS": "O",
+            "SA": "S",
+        }
         fixed = False
         new_num = 0
         forbidden_characters = "[^a-zA-Z0-9_]"
-        pdbline = pdbline.strip('\n')
+        pdbline = pdbline.strip("\n")
         # Some MD / Docking tools produce empty lines, leading to segfaults
         if len(pdbline.strip()) == 0:
             self.num_fixed_lines += 1
@@ -121,9 +168,9 @@ class PDBParser:
             self.num_fixed_lines += 1
             return None, lastnum
         # TER Entries also have continuing numbering, consider them as well
-        if pdbline.startswith('TER'):
+        if pdbline.startswith("TER"):
             new_num = lastnum + 1
-        if pdbline.startswith('ATOM'):
+        if pdbline.startswith("ATOM"):
             new_num = lastnum + 1
             current_num = int(pdbline[6:11])
             resnum = pdbline[22:27].strip()
@@ -132,73 +179,107 @@ class PDBParser:
             try:
                 int(resnum)
             except ValueError:
-                pdbline = pdbline[:22] + '   0 ' + pdbline[27:]
+                pdbline = pdbline[:22] + "   0 " + pdbline[27:]
                 fixed = True
             # Invalid characters in residue name
             if re.match(forbidden_characters, resname.strip()):
-                pdbline = pdbline[:17] + 'UNK ' + pdbline[21:]
+                pdbline = pdbline[:17] + "UNK " + pdbline[21:]
                 fixed = True
             if lastnum + 1 != current_num:
-                pdbline = pdbline[:6] + (5 - len(str(new_num))) * ' ' + str(new_num) + ' ' + pdbline[12:]
+                pdbline = (
+                    pdbline[:6]
+                    + (5 - len(str(new_num))) * " "
+                    + str(new_num)
+                    + " "
+                    + pdbline[12:]
+                )
                 fixed = True
             # No chain assigned
-            if pdbline[21] == ' ':
-                pdbline = pdbline[:21] + 'A' + pdbline[22:]
+            if pdbline[21] == " ":
+                pdbline = pdbline[:21] + "A" + pdbline[22:]
                 fixed = True
-            if pdbline.endswith('H'):
+            if pdbline.endswith("H"):
                 self.num_fixed_lines += 1
                 return None, lastnum
             # Sometimes, converted PDB structures contain PDBQT atom types. Fix that.
             for pdbqttype in pdbqt_conversion:
                 if pdbline.strip().endswith(pdbqttype):
-                    pdbline = pdbline.strip()[:-2] + ' ' + pdbqt_conversion[pdbqttype] + '\n'
+                    pdbline = (
+                        pdbline.strip()[:-2] + " " + pdbqt_conversion[pdbqttype] + "\n"
+                    )
                     self.num_fixed_lines += 1
-        if pdbline.startswith('HETATM'):
+        if pdbline.startswith("HETATM"):
             new_num = lastnum + 1
             try:
                 current_num = int(pdbline[6:11])
             except ValueError:
                 current_num = None
-                logger.debug(f'invalid HETATM entry: {pdbline}')
+                logger.debug(f"invalid HETATM entry: {pdbline}")
             if lastnum + 1 != current_num:
-                pdbline = pdbline[:6] + (5 - len(str(new_num))) * ' ' + str(new_num) + ' ' + pdbline[12:]
+                pdbline = (
+                    pdbline[:6]
+                    + (5 - len(str(new_num))) * " "
+                    + str(new_num)
+                    + " "
+                    + pdbline[12:]
+                )
                 fixed = True
             # No chain assigned or number assigned as chain
-            if pdbline[21] == ' ':
-                pdbline = pdbline[:21] + 'Z' + pdbline[22:]
+            if pdbline[21] == " ":
+                pdbline = pdbline[:21] + "Z" + pdbline[22:]
                 fixed = True
             # No residue number assigned
-            if pdbline[23:26] == '   ':
-                pdbline = pdbline[:23] + '999' + pdbline[26:]
+            if pdbline[23:26] == "   ":
+                pdbline = pdbline[:23] + "999" + pdbline[26:]
                 fixed = True
             # Non-standard Ligand Names
             ligname = pdbline[17:21].strip()
             if len(ligname) > 3:
-                pdbline = pdbline[:17] + ligname[:3] + ' ' + pdbline[21:]
+                pdbline = pdbline[:17] + ligname[:3] + " " + pdbline[21:]
                 fixed = True
             if re.match(forbidden_characters, ligname.strip()):
-                pdbline = pdbline[:17] + 'LIG ' + pdbline[21:]
+                pdbline = pdbline[:17] + "LIG " + pdbline[21:]
                 fixed = True
             if len(ligname.strip()) == 0:
-                pdbline = pdbline[:17] + 'LIG ' + pdbline[21:]
+                pdbline = pdbline[:17] + "LIG " + pdbline[21:]
                 fixed = True
-            if pdbline.endswith('H'):
+            if pdbline.endswith("H"):
                 self.num_fixed_lines += 1
                 return None, lastnum
             # Sometimes, converted PDB structures contain PDBQT atom types. Fix that.
             for pdbqttype in pdbqt_conversion:
                 if pdbline.strip().endswith(pdbqttype):
-                    pdbline = pdbline.strip()[:-2] + ' ' + pdbqt_conversion[pdbqttype] + ' '
+                    pdbline = (
+                        pdbline.strip()[:-2] + " " + pdbqt_conversion[pdbqttype] + " "
+                    )
                     self.num_fixed_lines += 1
         self.num_fixed_lines += 1 if fixed else 0
-        return pdbline + '\n', max(new_num, lastnum)
+        return pdbline + "\n", max(new_num, lastnum)
 
     def get_linkage(self, line):
         """Get the linkage information from a LINK entry PDB line."""
-        conf1, id1, chain1, pos1 = line[16].strip(), line[17:20].strip(), line[21].strip(), int(line[22:26])
-        conf2, id2, chain2, pos2 = line[46].strip(), line[47:50].strip(), line[51].strip(), int(line[52:56])
-        return self.covlinkage(id1=id1, chain1=chain1, pos1=pos1, conf1=conf1,
-                               id2=id2, chain2=chain2, pos2=pos2, conf2=conf2)
+        conf1, id1, chain1, pos1 = (
+            line[16].strip(),
+            line[17:20].strip(),
+            line[21].strip(),
+            int(line[22:26]),
+        )
+        conf2, id2, chain2, pos2 = (
+            line[46].strip(),
+            line[47:50].strip(),
+            line[51].strip(),
+            int(line[52:56]),
+        )
+        return self.covlinkage(
+            id1=id1,
+            chain1=chain1,
+            pos1=pos1,
+            conf1=conf1,
+            id2=id2,
+            chain2=chain2,
+            pos2=pos2,
+            conf2=conf2,
+        )
 
 
 class LigandFinder:
@@ -212,15 +293,20 @@ class LigandFinder:
         self.covalent = covalent
         self.mapper = mapper
         self.ligands = self.getligs()
-        self.excluded = sorted(list(self.lignames_all.difference(set(self.lignames_kept))))
+        self.excluded = sorted(
+            list(self.lignames_all.difference(set(self.lignames_kept)))
+        )
 
     def getpeptides(self, chain):
         """If peptide ligand chains are defined via the command line options,
         try to extract the underlying ligand formed by all residues in the
         given chain without water
         """
-        all_from_chain = [o for o in pybel.ob.OBResidueIter(
-            self.proteincomplex.OBMol) if o.GetChain() == chain]  # All residues from chain
+        all_from_chain = [
+            o
+            for o in pybel.ob.OBResidueIter(self.proteincomplex.OBMol)
+            if o.GetChain() == chain
+        ]  # All residues from chain
         if len(all_from_chain) == 0:
             return None
         else:
@@ -240,7 +326,9 @@ class LigandFinder:
             # Filter for ligands using lists
             ligand_residues, self.lignames_all, self.water = self.filter_for_ligands()
 
-            all_res_dict = {(a.GetName(), a.GetChain(), a.GetNum()): a for a in ligand_residues}
+            all_res_dict = {
+                (a.GetName(), a.GetChain(), a.GetNum()): a for a in ligand_residues
+            }
             self.lignames_kept = list(set([a.GetName() for a in ligand_residues]))
 
             if not config.BREAKCOMPOSITE:
@@ -249,22 +337,35 @@ class LigandFinder:
                 #  Find fragment linked by covalent bonds
                 res_kmers = self.identify_kmers(all_res_dict)
             else:
-                res_kmers = [[a, ] for a in ligand_residues]
-            logger.debug(f'{len(res_kmers)} ligand kmer(s) detected for closer inspection')
-            for kmer in res_kmers:  # iterate over all ligands and extract molecules + information
+                res_kmers = [[a,] for a in ligand_residues]
+            logger.debug(
+                f"{len(res_kmers)} ligand kmer(s) detected for closer inspection"
+            )
+            for (
+                kmer
+            ) in (
+                res_kmers
+            ):  # iterate over all ligands and extract molecules + information
                 if len(kmer) > config.MAX_COMPOSITE_LENGTH:
                     logger.debug(
-                        f'ligand kmer(s) filtered out with a length of {len(kmer)} fragments ({config.MAX_COMPOSITE_LENGTH} allowed)')
+                        f"ligand kmer(s) filtered out with a length of {len(kmer)} fragments ({config.MAX_COMPOSITE_LENGTH} allowed)"
+                    )
                 else:
                     ligands.append(self.extract_ligand(kmer))
 
         else:
             # Extract peptides from given chains
-            self.water = [o for o in pybel.ob.OBResidueIter(self.proteincomplex.OBMol) if o.GetResidueProperty(9)]
+            self.water = [
+                o
+                for o in pybel.ob.OBResidueIter(self.proteincomplex.OBMol)
+                if o.GetResidueProperty(9)
+            ]
             if config.PEPTIDES:
                 peptide_ligands = [self.getpeptides(chain) for chain in config.PEPTIDES]
             elif config.INTRA is not None:
-                peptide_ligands = [self.getpeptides(config.INTRA), ]
+                peptide_ligands = [
+                    self.getpeptides(config.INTRA),
+                ]
 
             ligands = [p for p in peptide_ligands if p is not None]
             self.covalent, self.lignames_kept, self.lignames_all = [], [], set()
@@ -273,35 +374,53 @@ class LigandFinder:
 
     def extract_ligand(self, kmer):
         """Extract the ligand by copying atoms and bonds and assign all information necessary for later steps."""
-        data = namedtuple('ligand', 'mol hetid chain position water members longname type atomorder can_to_pdb')
-        members = [(res.GetName(), res.GetChain(), int32_to_negative(res.GetNum())) for res in kmer]
+        data = namedtuple(
+            "ligand",
+            "mol hetid chain position water members longname type atomorder can_to_pdb",
+        )
+        members = [
+            (res.GetName(), res.GetChain(), int32_to_negative(res.GetNum()))
+            for res in kmer
+        ]
         members = sort_members_by_importance(members)
         rname, rchain, rnum = members[0]
-        logger.debug(f'finalizing extraction for ligand {rname}:{rchain}:{rnum} with {len(kmer)} elements')
+        logger.debug(
+            f"finalizing extraction for ligand {rname}:{rchain}:{rnum} with {len(kmer)} elements"
+        )
         names = [x[0] for x in members]
-        longname = '-'.join([x[0] for x in members])
+        longname = "-".join([x[0] for x in members])
 
         if config.PEPTIDES:
-            ligtype = 'PEPTIDE'
+            ligtype = "PEPTIDE"
         elif config.INTRA is not None:
-            ligtype = 'INTRA'
+            ligtype = "INTRA"
         else:
             # Classify a ligand by its HETID(s)
             ligtype = classify_by_name(names)
-        logger.debug(f'ligand classified as {ligtype}')
+        logger.debug(f"ligand classified as {ligtype}")
 
         hetatoms = set()
         for obresidue in kmer:
-            hetatoms_res = set([(obatom.GetIdx(), obatom) for obatom in pybel.ob.OBResidueAtomIter(obresidue)
-                                if obatom.GetAtomicNum() != 1])
+            hetatoms_res = set(
+                [
+                    (obatom.GetIdx(), obatom)
+                    for obatom in pybel.ob.OBResidueAtomIter(obresidue)
+                    if obatom.GetAtomicNum() != 1
+                ]
+            )
 
             if not config.ALTLOC:
                 # Remove alternative conformations (standard -> True)
-                hetatoms_res = set([atm for atm in hetatoms_res
-                                    if not self.mapper.mapid(atm[0], mtype='protein',
-                                                             to='internal') in self.altconformations])
+                hetatoms_res = set(
+                    [
+                        atm
+                        for atm in hetatoms_res
+                        if not self.mapper.mapid(atm[0], mtype="protein", to="internal")
+                        in self.altconformations
+                    ]
+                )
             hetatoms.update(hetatoms_res)
-        logger.debug(f'hetero atoms determined (n={len(hetatoms)})')
+        logger.debug(f"hetero atoms determined (n={len(hetatoms)})")
 
         hetatoms = dict(hetatoms)  # make it a dict with idx as key and OBAtom as value
         lig = pybel.ob.OBMol()  # new ligand mol
@@ -310,15 +429,24 @@ class LigandFinder:
             idx = obatom.GetIdx()
             lig.AddAtom(obatom)
             # ids of all neighbours of obatom
-            neighbours[idx] = set([neighbour_atom.GetIdx() for neighbour_atom
-                                   in pybel.ob.OBAtomAtomIter(obatom)]) & set(hetatoms.keys())
-        logger.debug(f'atom neighbours mapped')
+            neighbours[idx] = set(
+                [
+                    neighbour_atom.GetIdx()
+                    for neighbour_atom in pybel.ob.OBAtomAtomIter(obatom)
+                ]
+            ) & set(hetatoms.keys())
+        logger.debug(f"atom neighbours mapped")
 
         ##############################################################
         # map the old atom idx of OBMol to the new idx of the ligand #
         ##############################################################
 
-        newidx = dict(zip(hetatoms.keys(), [obatom.GetIdx() for obatom in pybel.ob.OBMolAtomIter(lig)]))
+        newidx = dict(
+            zip(
+                hetatoms.keys(),
+                [obatom.GetIdx() for obatom in pybel.ob.OBMolAtomIter(lig)],
+            )
+        )
         mapold = dict(zip(newidx.values(), newidx))
         # copy the bonds
         for obatom in hetatoms:
@@ -328,16 +456,16 @@ class LigandFinder:
         lig = pybel.Molecule(lig)
 
         # For kmers, the representative ids are chosen (first residue of kmer)
-        lig.data.update({'Name': rname, 'Chain': rchain, 'ResNr': rnum})
+        lig.data.update({"Name": rname, "Chain": rchain, "ResNr": rnum})
 
         # Check if a negative residue number is represented as a 32 bit integer
         if rnum > 10 ** 5:
             rnum = int32_to_negative(rnum)
 
-        lig.title = ':'.join((rname, rchain, str(rnum)))
+        lig.title = ":".join((rname, rchain, str(rnum)))
         self.mapper.ligandmaps[lig.title] = mapold
 
-        logger.debug('renumerated molecule generated')
+        logger.debug("renumerated molecule generated")
 
         if not config.NOPDBCANMAP:
             atomorder = canonicalize(lig)
@@ -348,9 +476,18 @@ class LigandFinder:
         if atomorder is not None:
             can_to_pdb = {atomorder[key - 1]: mapold[key] for key in mapold}
 
-        ligand = data(mol=lig, hetid=rname, chain=rchain, position=rnum, water=self.water,
-                      members=members, longname=longname, type=ligtype, atomorder=atomorder,
-                      can_to_pdb=can_to_pdb)
+        ligand = data(
+            mol=lig,
+            hetid=rname,
+            chain=rchain,
+            position=rnum,
+            water=self.water,
+            members=members,
+            longname=longname,
+            type=ligtype,
+            atomorder=atomorder,
+            can_to_pdb=can_to_pdb,
+        )
         return ligand
 
     def is_het_residue(self, obres):
@@ -375,20 +512,35 @@ class LigandFinder:
     def filter_for_ligands(self):
         """Given an OpenBabel Molecule, get all ligands, their names, and water"""
 
-        candidates1 = [o for o in pybel.ob.OBResidueIter(
-            self.proteincomplex.OBMol) if not o.GetResidueProperty(9) and self.is_het_residue(o)]
+        candidates1 = [
+            o
+            for o in pybel.ob.OBResidueIter(self.proteincomplex.OBMol)
+            if not o.GetResidueProperty(9) and self.is_het_residue(o)
+        ]
 
         if config.DNARECEPTOR:  # If DNA is the receptor, don't consider DNA as a ligand
-            candidates1 = [res for res in candidates1 if res.GetName() not in config.DNA + config.RNA]
+            candidates1 = [
+                res
+                for res in candidates1
+                if res.GetName() not in config.DNA + config.RNA
+            ]
         all_lignames = set([a.GetName() for a in candidates1])
 
-        water = [o for o in pybel.ob.OBResidueIter(self.proteincomplex.OBMol) if o.GetResidueProperty(9)]
+        water = [
+            o
+            for o in pybel.ob.OBResidueIter(self.proteincomplex.OBMol)
+            if o.GetResidueProperty(9)
+        ]
         # Filter out non-ligands
         if not config.KEEPMOD:  # Keep modified residues as ligands
-            candidates2 = [a for a in candidates1 if is_lig(a.GetName()) and a.GetName() not in self.modresidues]
+            candidates2 = [
+                a
+                for a in candidates1
+                if is_lig(a.GetName()) and a.GetName() not in self.modresidues
+            ]
         else:
             candidates2 = [a for a in candidates1 if is_lig(a.GetName())]
-        logger.debug(f'{len(candidates2)} ligand(s) after first filtering step')
+        logger.debug(f"{len(candidates2)} ligand(s) after first filtering step")
 
         ############################################
         # Filtering by counting and artifacts list #
@@ -397,7 +549,10 @@ class LigandFinder:
         unique_ligs = set(a.GetName() for a in candidates2)
         for ulig in unique_ligs:
             # Discard if appearing 15 times or more and is possible artifact
-            if ulig in config.biolip_list and [a.GetName() for a in candidates2].count(ulig) >= 15:
+            if (
+                ulig in config.biolip_list
+                and [a.GetName() for a in candidates2].count(ulig) >= 15
+            ):
                 artifacts.append(ulig)
 
         selected_ligands = [a for a in candidates2 if a.GetName() not in artifacts]
@@ -408,12 +563,19 @@ class LigandFinder:
         """Using the covalent linkage information, find out which fragments/subunits form a ligand."""
 
         # Remove all those not considered by ligands and pairings including alternate conformations
-        ligdoubles = [[(link.id1, link.chain1, link.pos1),
-                       (link.id2, link.chain2, link.pos2)] for link in
-                      [c for c in self.covalent if c.id1 in self.lignames_kept and c.id2 in self.lignames_kept
-                       and c.conf1 in ['A', ''] and c.conf2 in ['A', '']
-                       and (c.id1, c.chain1, c.pos1) in residues
-                       and (c.id2, c.chain2, c.pos2) in residues]]
+        ligdoubles = [
+            [(link.id1, link.chain1, link.pos1), (link.id2, link.chain2, link.pos2)]
+            for link in [
+                c
+                for c in self.covalent
+                if c.id1 in self.lignames_kept
+                and c.id2 in self.lignames_kept
+                and c.conf1 in ["A", ""]
+                and c.conf2 in ["A", ""]
+                and (c.id1, c.chain1, c.pos1) in residues
+                and (c.id2, c.chain2, c.pos2) in residues
+            ]
+        ]
         kmers = cluster_doubles(ligdoubles)
         if not kmers:  # No ligand kmers, just normal independent ligands
             return [[residues[res]] for res in residues]
@@ -429,7 +591,9 @@ class LigandFinder:
                     in_kmer.append((res.GetName(), res.GetChain(), res.GetNum()))
             for res in residues:
                 if res not in in_kmer:
-                    newres = [residues[res], ]
+                    newres = [
+                        residues[res],
+                    ]
                     res_kmers.append(newres)
             return res_kmers
 
@@ -438,26 +602,32 @@ class Mapper:
     """Provides functions for mapping atom IDs in the correct way"""
 
     def __init__(self):
-        self.proteinmap = None  # Map internal atom IDs of protein residues to original PDB Atom IDs
-        self.ligandmaps = {}  # Map IDs of new ligand molecules to internal IDs (or PDB IDs?)
+        self.proteinmap = (
+            None  # Map internal atom IDs of protein residues to original PDB Atom IDs
+        )
+        self.ligandmaps = (
+            {}
+        )  # Map IDs of new ligand molecules to internal IDs (or PDB IDs?)
         self.original_structure = None
 
-    def mapid(self, idx, mtype, bsid=None, to='original'):  # Mapping to original IDs is standard for ligands
-        if mtype == 'reversed':  # Needed to map internal ID back to original protein ID
+    def mapid(
+        self, idx, mtype, bsid=None, to="original"
+    ):  # Mapping to original IDs is standard for ligands
+        if mtype == "reversed":  # Needed to map internal ID back to original protein ID
             return self.reversed_proteinmap[idx]
-        if mtype == 'protein':
+        if mtype == "protein":
             return self.proteinmap[idx]
-        elif mtype == 'ligand':
-            if to == 'internal':
+        elif mtype == "ligand":
+            if to == "internal":
                 return self.ligandmaps[bsid][idx]
-            elif to == 'original':
+            elif to == "original":
                 return self.proteinmap[self.ligandmaps[bsid][idx]]
 
     def id_to_atom(self, idx):
         """Returns the atom for a given original ligand ID.
         To do this, the ID is mapped to the protein first and then the atom returned.
         """
-        mapped_idx = self.mapid(idx, 'reversed')
+        mapped_idx = self.mapid(idx, "reversed")
         return pybel.Atom(self.original_structure.GetAtom(mapped_idx))
 
 
@@ -476,10 +646,15 @@ class Mol:
     def hydrophobic_atoms(self, all_atoms):
         """Select all carbon atoms which have only carbons and/or hydrogens as direct neighbors."""
         atom_set = []
-        data = namedtuple('hydrophobic', 'atom orig_atom orig_idx')
-        atm = [a for a in all_atoms if a.atomicnum == 6 and set([natom.GetAtomicNum() for natom
-                                                                 in pybel.ob.OBAtomAtomIter(a.OBAtom)]).issubset(
-            {1, 6})]
+        data = namedtuple("hydrophobic", "atom orig_atom orig_idx")
+        atm = [
+            a
+            for a in all_atoms
+            if a.atomicnum == 6
+            and set(
+                [natom.GetAtomicNum() for natom in pybel.ob.OBAtomAtomIter(a.OBAtom)]
+            ).issubset({1, 6})
+        ]
         for atom in atm:
             orig_idx = self.Mapper.mapid(atom.idx, mtype=self.mtype, bsid=self.bsid)
             orig_atom = self.Mapper.id_to_atom(orig_idx)
@@ -489,45 +664,88 @@ class Mol:
 
     def find_hba(self, all_atoms):
         """Find all possible hydrogen bond acceptors"""
-        data = namedtuple('hbondacceptor', 'a a_orig_atom a_orig_idx type')
+        data = namedtuple("hbondacceptor", "a a_orig_atom a_orig_idx type")
         a_set = []
         for atom in filter(lambda at: at.OBAtom.IsHbondAcceptor(), all_atoms):
-            if atom.atomicnum not in [9, 17, 35, 53] and atom.idx not in self.altconf:  # Exclude halogen atoms
-                a_orig_idx = self.Mapper.mapid(atom.idx, mtype=self.mtype, bsid=self.bsid)
+            if (
+                atom.atomicnum not in [9, 17, 35, 53] and atom.idx not in self.altconf
+            ):  # Exclude halogen atoms
+                a_orig_idx = self.Mapper.mapid(
+                    atom.idx, mtype=self.mtype, bsid=self.bsid
+                )
                 a_orig_atom = self.Mapper.id_to_atom(a_orig_idx)
-                a_set.append(data(a=atom, a_orig_atom=a_orig_atom, a_orig_idx=a_orig_idx, type='regular'))
+                a_set.append(
+                    data(
+                        a=atom,
+                        a_orig_atom=a_orig_atom,
+                        a_orig_idx=a_orig_idx,
+                        type="regular",
+                    )
+                )
         a_set = sorted(a_set, key=lambda x: x.a_orig_idx)
         return a_set
 
     def find_hbd(self, all_atoms, hydroph_atoms):
         """Find all possible strong and weak hydrogen bonds donors (all hydrophobic C-H pairings)"""
         donor_pairs = []
-        data = namedtuple('hbonddonor', 'd d_orig_atom d_orig_idx h type')
-        for donor in [a for a in all_atoms if a.OBAtom.IsHbondDonor() and a.idx not in self.altconf]:
+        data = namedtuple("hbonddonor", "d d_orig_atom d_orig_idx h type")
+        for donor in [
+            a
+            for a in all_atoms
+            if a.OBAtom.IsHbondDonor() and a.idx not in self.altconf
+        ]:
             in_ring = False
             if not in_ring:
-                for adj_atom in [a for a in pybel.ob.OBAtomAtomIter(donor.OBAtom) if a.IsHbondDonorH()]:
-                    d_orig_idx = self.Mapper.mapid(donor.idx, mtype=self.mtype, bsid=self.bsid)
+                for adj_atom in [
+                    a
+                    for a in pybel.ob.OBAtomAtomIter(donor.OBAtom)
+                    if a.IsHbondDonorH()
+                ]:
+                    d_orig_idx = self.Mapper.mapid(
+                        donor.idx, mtype=self.mtype, bsid=self.bsid
+                    )
                     d_orig_atom = self.Mapper.id_to_atom(d_orig_idx)
-                    donor_pairs.append(data(d=donor, d_orig_atom=d_orig_atom, d_orig_idx=d_orig_idx,
-                                            h=pybel.Atom(adj_atom), type='regular'))
+                    donor_pairs.append(
+                        data(
+                            d=donor,
+                            d_orig_atom=d_orig_atom,
+                            d_orig_idx=d_orig_idx,
+                            h=pybel.Atom(adj_atom),
+                            type="regular",
+                        )
+                    )
         for carbon in hydroph_atoms:
-            for adj_atom in [a for a in pybel.ob.OBAtomAtomIter(carbon.atom.OBAtom) if a.GetAtomicNum() == 1]:
-                d_orig_idx = self.Mapper.mapid(carbon.atom.idx, mtype=self.mtype, bsid=self.bsid)
+            for adj_atom in [
+                a
+                for a in pybel.ob.OBAtomAtomIter(carbon.atom.OBAtom)
+                if a.GetAtomicNum() == 1
+            ]:
+                d_orig_idx = self.Mapper.mapid(
+                    carbon.atom.idx, mtype=self.mtype, bsid=self.bsid
+                )
                 d_orig_atom = self.Mapper.id_to_atom(d_orig_idx)
-                donor_pairs.append(data(d=carbon, d_orig_atom=d_orig_atom,
-                                        d_orig_idx=d_orig_idx, h=pybel.Atom(adj_atom), type='weak'))
+                donor_pairs.append(
+                    data(
+                        d=carbon,
+                        d_orig_atom=d_orig_atom,
+                        d_orig_idx=d_orig_idx,
+                        h=pybel.Atom(adj_atom),
+                        type="weak",
+                    )
+                )
         donor_pairs = sorted(donor_pairs, key=lambda x: (x.d_orig_idx, x.h.idx))
         return donor_pairs
 
     def find_rings(self, mol, all_atoms):
         """Find rings and return only aromatic.
         Rings have to be sufficiently planar OR be detected by OpenBabel as aromatic."""
-        data = namedtuple('aromatic_ring', 'atoms orig_atoms atoms_orig_idx normal obj center type')
+        data = namedtuple(
+            "aromatic_ring", "atoms orig_atoms atoms_orig_idx normal obj center type"
+        )
         rings = []
-        aromatic_amino = ['TYR', 'TRP', 'HIS', 'PHE']
+        aromatic_amino = ["TYR", "TRP", "HIS", "PHE"]
         ring_candidates = mol.OBMol.GetSSSR()
-        logger.debug(f'number of aromatic ring candidates: {len(ring_candidates)}')
+        logger.debug(f"number of aromatic ring candidates: {len(ring_candidates)}")
         # Check here first for ligand rings not being detected as aromatic by Babel and check for planarity
         for ring in ring_candidates:
             r_atoms = [a for a in all_atoms if ring.IsMember(a.OBAtom)]
@@ -535,28 +753,42 @@ class Mol:
             if 4 < len(r_atoms) <= 6:
                 res = list(set([whichrestype(a) for a in r_atoms]))
                 # re-sort ring atoms for only ligands, because HETATM numbering is not canonical in OpenBabel
-                if res[0] == 'UNL':
-                    ligand_orig_idx = [self.Mapper.ligandmaps[self.bsid][a.idx] for a in r_atoms]
+                if res[0] == "UNL":
+                    ligand_orig_idx = [
+                        self.Mapper.ligandmaps[self.bsid][a.idx] for a in r_atoms
+                    ]
                     sort_order = np.argsort(np.array(ligand_orig_idx))
                     r_atoms = [r_atoms[i] for i in sort_order]
-                if ring.IsAromatic() or res[0] in aromatic_amino or ring_is_planar(ring, r_atoms):
+                if (
+                    ring.IsAromatic()
+                    or res[0] in aromatic_amino
+                    or ring_is_planar(ring, r_atoms)
+                ):
                     # Causes segfault with OpenBabel 2.3.2, so deactivated
                     # typ = ring.GetType() if not ring.GetType() == '' else 'unknown'
                     # Alternative typing
-                    ring_type = '%s-membered' % len(r_atoms)
-                    ring_atms = [r_atoms[a].coords for a in [0, 2, 4]]  # Probe atoms for normals, assuming planarity
+                    ring_type = "%s-membered" % len(r_atoms)
+                    ring_atms = [
+                        r_atoms[a].coords for a in [0, 2, 4]
+                    ]  # Probe atoms for normals, assuming planarity
                     ringv1 = vector(ring_atms[0], ring_atms[1])
                     ringv2 = vector(ring_atms[2], ring_atms[0])
-                    atoms_orig_idx = [self.Mapper.mapid(r_atom.idx, mtype=self.mtype,
-                                                        bsid=self.bsid) for r_atom in r_atoms]
+                    atoms_orig_idx = [
+                        self.Mapper.mapid(r_atom.idx, mtype=self.mtype, bsid=self.bsid)
+                        for r_atom in r_atoms
+                    ]
                     orig_atoms = [self.Mapper.id_to_atom(idx) for idx in atoms_orig_idx]
-                    rings.append(data(atoms=r_atoms,
-                                      orig_atoms=orig_atoms,
-                                      atoms_orig_idx=atoms_orig_idx,
-                                      normal=normalize_vector(np.cross(ringv1, ringv2)),
-                                      obj=ring,
-                                      center=centroid([ra.coords for ra in r_atoms]),
-                                      type=ring_type))
+                    rings.append(
+                        data(
+                            atoms=r_atoms,
+                            orig_atoms=orig_atoms,
+                            atoms_orig_idx=atoms_orig_idx,
+                            normal=normalize_vector(np.cross(ringv1, ringv2)),
+                            obj=ring,
+                            center=centroid([ra.coords for ra in r_atoms]),
+                            type=ring_type,
+                        )
+                    )
         return rings
 
     def get_hydrophobic_atoms(self):
@@ -566,16 +798,24 @@ class Mol:
         return self.hbond_acc_atoms
 
     def get_hbd(self):
-        return [don_pair for don_pair in self.hbond_don_atom_pairs if don_pair.type == 'regular']
+        return [
+            don_pair
+            for don_pair in self.hbond_don_atom_pairs
+            if don_pair.type == "regular"
+        ]
 
     def get_weak_hbd(self):
-        return [don_pair for don_pair in self.hbond_don_atom_pairs if don_pair.type == 'weak']
+        return [
+            don_pair
+            for don_pair in self.hbond_don_atom_pairs
+            if don_pair.type == "weak"
+        ]
 
     def get_pos_charged(self):
-        return [charge for charge in self.charged if charge.type == 'positive']
+        return [charge for charge in self.charged if charge.type == "positive"]
 
     def get_neg_charged(self):
-        return [charge for charge in self.charged if charge.type == 'negative']
+        return [charge for charge in self.charged if charge.type == "negative"]
 
 
 class PLInteraction:
@@ -592,65 +832,135 @@ class PLInteraction:
         self.altconf = protcomplex.altconf
         # #@todo Refactor code to combine different directionality
 
-        self.saltbridge_lneg = saltbridge(self.bindingsite.get_pos_charged(), self.ligand.get_neg_charged(), True)
-        self.saltbridge_pneg = saltbridge(self.ligand.get_pos_charged(), self.bindingsite.get_neg_charged(), False)
-
-        self.all_hbonds_ldon = hbonds(self.bindingsite.get_hba(),
-                                      self.ligand.get_hbd(), False, 'strong')
-        self.all_hbonds_pdon = hbonds(self.ligand.get_hba(),
-                                      self.bindingsite.get_hbd(), True, 'strong')
-
-        self.hbonds_ldon = self.refine_hbonds_ldon(self.all_hbonds_ldon, self.saltbridge_lneg,
-                                                   self.saltbridge_pneg)
-        self.hbonds_pdon = self.refine_hbonds_pdon(self.all_hbonds_pdon, self.saltbridge_lneg,
-                                                   self.saltbridge_pneg)
+        self.saltbridge_lneg = saltbridge(
+            self.bindingsite.get_pos_charged(), self.ligand.get_neg_charged(), True
+        )
+        self.saltbridge_pneg = saltbridge(
+            self.ligand.get_pos_charged(), self.bindingsite.get_neg_charged(), False
+        )
+
+        self.all_hbonds_ldon = hbonds(
+            self.bindingsite.get_hba(), self.ligand.get_hbd(), False, "strong"
+        )
+        self.all_hbonds_pdon = hbonds(
+            self.ligand.get_hba(), self.bindingsite.get_hbd(), True, "strong"
+        )
+
+        self.hbonds_ldon = self.refine_hbonds_ldon(
+            self.all_hbonds_ldon, self.saltbridge_lneg, self.saltbridge_pneg
+        )
+        self.hbonds_pdon = self.refine_hbonds_pdon(
+            self.all_hbonds_pdon, self.saltbridge_lneg, self.saltbridge_pneg
+        )
 
         self.pistacking = pistacking(self.bindingsite.rings, self.ligand.rings)
 
-        self.all_pi_cation_laro = pication(self.ligand.rings, self.bindingsite.get_pos_charged(), True)
-        self.pication_paro = pication(self.bindingsite.rings, self.ligand.get_pos_charged(), False)
-
-        self.pication_laro = self.refine_pi_cation_laro(self.all_pi_cation_laro, self.pistacking)
-
-        self.all_hydrophobic_contacts = hydrophobic_interactions(self.bindingsite.get_hydrophobic_atoms(),
-                                                                 self.ligand.get_hydrophobic_atoms())
-        self.hydrophobic_contacts = self.refine_hydrophobic(self.all_hydrophobic_contacts, self.pistacking)
-        self.halogen_bonds = halogen(self.bindingsite.halogenbond_acc, self.ligand.halogenbond_don)
-        self.water_bridges = water_bridges(self.bindingsite.get_hba(), self.ligand.get_hba(),
-                                           self.bindingsite.get_hbd(), self.ligand.get_hbd(),
-                                           self.ligand.water)
-
-        self.water_bridges = self.refine_water_bridges(self.water_bridges, self.hbonds_ldon, self.hbonds_pdon)
-
-        self.metal_complexes = metal_complexation(self.ligand.metals, self.ligand.metal_binding,
-                                                  self.bindingsite.metal_binding)
+        self.all_pi_cation_laro = pication(
+            self.ligand.rings, self.bindingsite.get_pos_charged(), True
+        )
+        self.pication_paro = pication(
+            self.bindingsite.rings, self.ligand.get_pos_charged(), False
+        )
+
+        self.pication_laro = self.refine_pi_cation_laro(
+            self.all_pi_cation_laro, self.pistacking
+        )
+
+        self.all_hydrophobic_contacts = hydrophobic_interactions(
+            self.bindingsite.get_hydrophobic_atoms(),
+            self.ligand.get_hydrophobic_atoms(),
+        )
+        self.hydrophobic_contacts = self.refine_hydrophobic(
+            self.all_hydrophobic_contacts, self.pistacking
+        )
+        self.halogen_bonds = halogen(
+            self.bindingsite.halogenbond_acc, self.ligand.halogenbond_don
+        )
+        self.water_bridges = water_bridges(
+            self.bindingsite.get_hba(),
+            self.ligand.get_hba(),
+            self.bindingsite.get_hbd(),
+            self.ligand.get_hbd(),
+            self.ligand.water,
+        )
+
+        self.water_bridges = self.refine_water_bridges(
+            self.water_bridges, self.hbonds_ldon, self.hbonds_pdon
+        )
+
+        self.metal_complexes = metal_complexation(
+            self.ligand.metals,
+            self.ligand.metal_binding,
+            self.bindingsite.metal_binding,
+        )
 
         self.all_itypes = self.saltbridge_lneg + self.saltbridge_pneg + self.hbonds_pdon
-        self.all_itypes = self.all_itypes + self.hbonds_ldon + self.pistacking + self.pication_laro + self.pication_paro
-        self.all_itypes = self.all_itypes + self.hydrophobic_contacts + self.halogen_bonds + self.water_bridges
+        self.all_itypes = (
+            self.all_itypes
+            + self.hbonds_ldon
+            + self.pistacking
+            + self.pication_laro
+            + self.pication_paro
+        )
+        self.all_itypes = (
+            self.all_itypes
+            + self.hydrophobic_contacts
+            + self.halogen_bonds
+            + self.water_bridges
+        )
         self.all_itypes = self.all_itypes + self.metal_complexes
 
         self.no_interactions = all(len(i) == 0 for i in self.all_itypes)
-        self.unpaired_hba, self.unpaired_hbd, self.unpaired_hal = self.find_unpaired_ligand()
-        self.unpaired_hba_orig_idx = [self.Mapper.mapid(atom.idx, mtype='ligand', bsid=self.ligand.bsid)
-                                      for atom in self.unpaired_hba]
-        self.unpaired_hbd_orig_idx = [self.Mapper.mapid(atom.idx, mtype='ligand', bsid=self.ligand.bsid)
-                                      for atom in self.unpaired_hbd]
-        self.unpaired_hal_orig_idx = [self.Mapper.mapid(atom.idx, mtype='ligand', bsid=self.ligand.bsid)
-                                      for atom in self.unpaired_hal]
-        self.num_unpaired_hba, self.num_unpaired_hbd = len(self.unpaired_hba), len(self.unpaired_hbd)
+        (
+            self.unpaired_hba,
+            self.unpaired_hbd,
+            self.unpaired_hal,
+        ) = self.find_unpaired_ligand()
+        self.unpaired_hba_orig_idx = [
+            self.Mapper.mapid(atom.idx, mtype="ligand", bsid=self.ligand.bsid)
+            for atom in self.unpaired_hba
+        ]
+        self.unpaired_hbd_orig_idx = [
+            self.Mapper.mapid(atom.idx, mtype="ligand", bsid=self.ligand.bsid)
+            for atom in self.unpaired_hbd
+        ]
+        self.unpaired_hal_orig_idx = [
+            self.Mapper.mapid(atom.idx, mtype="ligand", bsid=self.ligand.bsid)
+            for atom in self.unpaired_hal
+        ]
+        self.num_unpaired_hba, self.num_unpaired_hbd = (
+            len(self.unpaired_hba),
+            len(self.unpaired_hbd),
+        )
         self.num_unpaired_hal = len(self.unpaired_hal)
 
         # Exclude empty chains (coming from ligand as a target, from metal complexes)
-        self.interacting_chains = sorted(list(set([i.reschain for i in self.all_itypes
-                                                   if i.reschain not in [' ', None]])))
+        self.interacting_chains = sorted(
+            list(
+                set(
+                    [
+                        i.reschain
+                        for i in self.all_itypes
+                        if i.reschain not in [" ", None]
+                    ]
+                )
+            )
+        )
 
         # Get all interacting residues, excluding ligand and water molecules
-        self.interacting_res = list(set([''.join([str(i.resnr), str(i.reschain)]) for i in self.all_itypes
-                                         if i.restype not in ['LIG', 'HOH']]))
+        self.interacting_res = list(
+            set(
+                [
+                    "".join([str(i.resnr), str(i.reschain)])
+                    for i in self.all_itypes
+                    if i.restype not in ["LIG", "HOH"]
+                ]
+            )
+        )
         if len(self.interacting_res) != 0:
             logger.info(
-                f'ligand interacts with {len(self.interacting_res)} binding site residue(s) in chain(s) {self.interacting_chains}')
+                f"ligand interacts with {len(self.interacting_res)} binding site residue(s) in chain(s) {self.interacting_chains}"
+            )
             interactions_list = []
             num_saltbridges = len(self.saltbridge_lneg + self.saltbridge_pneg)
             num_hbonds = len(self.hbonds_ldon + self.hbonds_pdon)
@@ -659,34 +969,49 @@ class PLInteraction:
             num_halogen = len(self.halogen_bonds)
             num_waterbridges = len(self.water_bridges)
             if num_saltbridges != 0:
-                interactions_list.append('%i salt bridge(s)' % num_saltbridges)
+                interactions_list.append("%i salt bridge(s)" % num_saltbridges)
             if num_hbonds != 0:
-                interactions_list.append('%i hydrogen bond(s)' % num_hbonds)
+                interactions_list.append("%i hydrogen bond(s)" % num_hbonds)
             if num_pication != 0:
-                interactions_list.append('%i pi-cation interaction(s)' % num_pication)
+                interactions_list.append("%i pi-cation interaction(s)" % num_pication)
             if num_pistack != 0:
-                interactions_list.append('%i pi-stacking(s)' % num_pistack)
+                interactions_list.append("%i pi-stacking(s)" % num_pistack)
             if num_halogen != 0:
-                interactions_list.append('%i halogen bond(s)' % num_halogen)
+                interactions_list.append("%i halogen bond(s)" % num_halogen)
             if num_waterbridges != 0:
-                interactions_list.append('%i water bridge(s)' % num_waterbridges)
+                interactions_list.append("%i water bridge(s)" % num_waterbridges)
             if not len(interactions_list) == 0:
-                logger.info(f'complex uses {interactions_list}')
+                logger.info(f"complex uses {interactions_list}")
         else:
-            logger.info('no interactions for this ligand')
+            logger.info("no interactions for this ligand")
 
     def find_unpaired_ligand(self):
         """Identify unpaired functional in groups in ligands, involving H-Bond donors, acceptors, halogen bond donors.
         """
         unpaired_hba, unpaired_hbd, unpaired_hal = [], [], []
         # Unpaired hydrogen bond acceptors/donors in ligand (not used for hydrogen bonds/water, salt bridges/mcomplex)
-        involved_atoms = [hbond.a.idx for hbond in self.hbonds_pdon] + [hbond.d.idx for hbond in self.hbonds_ldon]
-        [[involved_atoms.append(atom.idx) for atom in sb.negative.atoms] for sb in self.saltbridge_lneg]
-        [[involved_atoms.append(atom.idx) for atom in sb.positive.atoms] for sb in self.saltbridge_pneg]
+        involved_atoms = [hbond.a.idx for hbond in self.hbonds_pdon] + [
+            hbond.d.idx for hbond in self.hbonds_ldon
+        ]
+        [
+            [involved_atoms.append(atom.idx) for atom in sb.negative.atoms]
+            for sb in self.saltbridge_lneg
+        ]
+        [
+            [involved_atoms.append(atom.idx) for atom in sb.positive.atoms]
+            for sb in self.saltbridge_pneg
+        ]
         [involved_atoms.append(wb.a.idx) for wb in self.water_bridges if wb.protisdon]
-        [involved_atoms.append(wb.d.idx) for wb in self.water_bridges if not wb.protisdon]
-        [involved_atoms.append(mcomplex.target.atom.idx) for mcomplex in self.metal_complexes
-         if mcomplex.location == 'ligand']
+        [
+            involved_atoms.append(wb.d.idx)
+            for wb in self.water_bridges
+            if not wb.protisdon
+        ]
+        [
+            involved_atoms.append(mcomplex.target.atom.idx)
+            for mcomplex in self.metal_complexes
+            if mcomplex.location == "ligand"
+        ]
         for atom in [hba.a for hba in self.ligand.get_hba()]:
             if atom.idx not in involved_atoms:
                 unpaired_hba.append(atom)
@@ -708,7 +1033,10 @@ class PLInteraction:
         #  1. Rings interacting via stacking can't have additional hydrophobic contacts between each other.
         for pistack, h in itertools.product(pistacks, all_h):
             h1, h2 = h.bsatom.idx, h.ligatom.idx
-            brs, lrs = [p1.idx for p1 in pistack.proteinring.atoms], [p2.idx for p2 in pistack.ligandring.atoms]
+            brs, lrs = (
+                [p1.idx for p1 in pistack.proteinring.atoms],
+                [p2.idx for p2 in pistack.ligandring.atoms],
+            )
             if h1 in brs and h2 in lrs:
                 sel[(h1, h2)] = "EXCLUDE"
         hydroph = [h for h in all_h if not (h.bsatom.idx, h.ligatom.idx) in sel]
@@ -727,7 +1055,9 @@ class PLInteraction:
         #  3. If a protein atom interacts with several neighboring ligand atoms, just keep the one with the closest dist
         for h in hydroph:
             if h.bsatom.idx not in bsclust:
-                bsclust[h.bsatom.idx] = [h, ]
+                bsclust[h.bsatom.idx] = [
+                    h,
+                ]
             else:
                 bsclust[h.bsatom.idx].append(h)
 
@@ -753,10 +1083,12 @@ class PLInteraction:
 
             tuples = list(set(tuples))
             tuples = sorted(tuples, key=itemgetter(1))
-            clusters = cluster_doubles(tuples)  # Cluster connected atoms (i.e. find hydrophobic patches)
+            clusters = cluster_doubles(
+                tuples
+            )  # Cluster connected atoms (i.e. find hydrophobic patches)
 
             for cluster in clusters:
-                min_dist = float('inf')
+                min_dist = float("inf")
                 min_h = None
                 for atm_idx in cluster:
                     h = idx_to_h[atm_idx]
@@ -766,7 +1098,9 @@ class PLInteraction:
                 hydroph_final.append(min_h)
         before, reduced = len(all_h), len(hydroph_final)
         if not before == 0 and not before == reduced:
-            logger.info(f'reduced number of hydrophobic contacts from {before} to {reduced}')
+            logger.info(
+                f"reduced number of hydrophobic contacts from {before} to {reduced}"
+            )
         return hydroph_final
 
     def refine_hbonds_ldon(self, all_hbonds, salt_lneg, salt_pneg):
@@ -775,11 +1109,17 @@ class PLInteraction:
         for hbond in all_hbonds:
             i_set[hbond] = False
             for salt in salt_pneg:
-                protidx, ligidx = [at.idx for at in salt.negative.atoms], [at.idx for at in salt.positive.atoms]
+                protidx, ligidx = (
+                    [at.idx for at in salt.negative.atoms],
+                    [at.idx for at in salt.positive.atoms],
+                )
                 if hbond.d.idx in ligidx and hbond.a.idx in protidx:
                     i_set[hbond] = True
             for salt in salt_lneg:
-                protidx, ligidx = [at.idx for at in salt.positive.atoms], [at.idx for at in salt.negative.atoms]
+                protidx, ligidx = (
+                    [at.idx for at in salt.positive.atoms],
+                    [at.idx for at in salt.negative.atoms],
+                )
                 if hbond.d.idx in ligidx and hbond.a.idx in protidx:
                     i_set[hbond] = True
 
@@ -802,11 +1142,17 @@ class PLInteraction:
         for hbond in all_hbonds:
             i_set[hbond] = False
             for salt in salt_lneg:
-                protidx, ligidx = [at.idx for at in salt.positive.atoms], [at.idx for at in salt.negative.atoms]
+                protidx, ligidx = (
+                    [at.idx for at in salt.positive.atoms],
+                    [at.idx for at in salt.negative.atoms],
+                )
                 if hbond.a.idx in ligidx and hbond.d.idx in protidx:
                     i_set[hbond] = True
             for salt in salt_pneg:
-                protidx, ligidx = [at.idx for at in salt.negative.atoms], [at.idx for at in salt.positive.atoms]
+                protidx, ligidx = (
+                    [at.idx for at in salt.negative.atoms],
+                    [at.idx for at in salt.positive.atoms],
+                )
                 if hbond.a.idx in ligidx and hbond.d.idx in protidx:
                     i_set[hbond] = True
 
@@ -830,7 +1176,10 @@ class PLInteraction:
         for picat in all_picat:
             exclude = False
             for stack in stacks:
-                if whichrestype(stack.proteinring.atoms[0]) == 'HIS' and picat.ring.obj == stack.ligandring.obj:
+                if (
+                    whichrestype(stack.proteinring.atoms[0]) == "HIS"
+                    and picat.ring.obj == stack.ligandring.obj
+                ):
                     exclude = True
             if not exclude:
                 i_set.append(picat)
@@ -849,18 +1198,27 @@ class PLInteraction:
             if (wbridge.water.idx, wbridge.a.idx) not in wb_dict:
                 wb_dict[(wbridge.water.idx, wbridge.a.idx)] = wbridge
             else:
-                if abs(omega - wb_dict[(wbridge.water.idx, wbridge.a.idx)].w_angle) < abs(omega - wbridge.w_angle):
+                if abs(
+                    omega - wb_dict[(wbridge.water.idx, wbridge.a.idx)].w_angle
+                ) < abs(omega - wbridge.w_angle):
                     wb_dict[(wbridge.water.idx, wbridge.a.idx)] = wbridge
         for wb_tuple in wb_dict:
             water, acceptor = wb_tuple
             if water not in wb_dict2:
-                wb_dict2[water] = [(abs(omega - wb_dict[wb_tuple].w_angle), wb_dict[wb_tuple]), ]
+                wb_dict2[water] = [
+                    (abs(omega - wb_dict[wb_tuple].w_angle), wb_dict[wb_tuple]),
+                ]
             elif len(wb_dict2[water]) == 1:
-                wb_dict2[water].append((abs(omega - wb_dict[wb_tuple].w_angle), wb_dict[wb_tuple]))
+                wb_dict2[water].append(
+                    (abs(omega - wb_dict[wb_tuple].w_angle), wb_dict[wb_tuple])
+                )
                 wb_dict2[water] = sorted(wb_dict2[water], key=lambda x: x[0])
             else:
                 if wb_dict2[water][1][0] < abs(omega - wb_dict[wb_tuple].w_angle):
-                    wb_dict2[water] = [wb_dict2[water][0], (wb_dict[wb_tuple].w_angle, wb_dict[wb_tuple])]
+                    wb_dict2[water] = [
+                        wb_dict2[water][0],
+                        (wb_dict[wb_tuple].w_angle, wb_dict[wb_tuple]),
+                    ]
 
         filtered_wb = []
         for fwbridges in wb_dict2.values():
@@ -871,12 +1229,19 @@ class PLInteraction:
 class BindingSite(Mol):
     def __init__(self, atoms, protcomplex, cclass, altconf, min_dist, mapper):
         """Find all relevant parts which could take part in interactions"""
-        Mol.__init__(self, altconf, mapper, mtype='protein', bsid=None)
+        Mol.__init__(self, altconf, mapper, mtype="protein", bsid=None)
         self.complex = cclass
         self.full_mol = protcomplex
         self.all_atoms = atoms
         self.min_dist = min_dist  # Minimum distance of bs res to ligand
-        self.bs_res = list(set([''.join([str(whichresnumber(a)), whichchain(a)]) for a in self.all_atoms]))  # e.g. 47A
+        self.bs_res = list(
+            set(
+                [
+                    "".join([str(whichresnumber(a)), whichchain(a)])
+                    for a in self.all_atoms
+                ]
+            )
+        )  # e.g. 47A
         self.rings = self.find_rings(self.full_mol, self.all_atoms)
         self.hydroph_atoms = self.hydrophobic_atoms(self.all_atoms)
         self.hbond_acc_atoms = self.find_hba(self.all_atoms)
@@ -887,118 +1252,228 @@ class BindingSite(Mol):
 
     def find_hal(self, atoms):
         """Look for halogen bond acceptors (Y-{O|P|N|S}, with Y=C,P,S)"""
-        data = namedtuple('hal_acceptor', 'o o_orig_idx y y_orig_idx')
+        data = namedtuple("hal_acceptor", "o o_orig_idx y y_orig_idx")
         a_set = []
         # All oxygens, nitrogen, sulfurs with neighboring carbon, phosphor, nitrogen or sulfur
         for a in [at for at in atoms if at.atomicnum in [8, 7, 16]]:
-            n_atoms = [na for na in pybel.ob.OBAtomAtomIter(a.OBAtom) if na.GetAtomicNum() in [6, 7, 15, 16]]
+            n_atoms = [
+                na
+                for na in pybel.ob.OBAtomAtomIter(a.OBAtom)
+                if na.GetAtomicNum() in [6, 7, 15, 16]
+            ]
             if len(n_atoms) == 1:  # Proximal atom
                 o_orig_idx = self.Mapper.mapid(a.idx, mtype=self.mtype, bsid=self.bsid)
-                y_orig_idx = self.Mapper.mapid(n_atoms[0].GetIdx(), mtype=self.mtype, bsid=self.bsid)
-                a_set.append(data(o=a, o_orig_idx=o_orig_idx, y=pybel.Atom(n_atoms[0]), y_orig_idx=y_orig_idx))
+                y_orig_idx = self.Mapper.mapid(
+                    n_atoms[0].GetIdx(), mtype=self.mtype, bsid=self.bsid
+                )
+                a_set.append(
+                    data(
+                        o=a,
+                        o_orig_idx=o_orig_idx,
+                        y=pybel.Atom(n_atoms[0]),
+                        y_orig_idx=y_orig_idx,
+                    )
+                )
         return a_set
 
     def find_charged(self, mol):
         """Looks for positive charges in arginine, histidine or lysine, for negative in aspartic and glutamic acid."""
-        data = namedtuple('pcharge', 'atoms atoms_orig_idx type center restype resnr reschain')
+        data = namedtuple(
+            "pcharge", "atoms atoms_orig_idx type center restype resnr reschain"
+        )
         a_set = []
         # Iterate through all residue, exclude those in chains defined as peptides
-        for res in [r for r in pybel.ob.OBResidueIter(mol.OBMol) if not r.GetChain() in config.PEPTIDES]:
+        for res in [
+            r
+            for r in pybel.ob.OBResidueIter(mol.OBMol)
+            if not r.GetChain() in config.PEPTIDES
+        ]:
             if config.INTRA is not None:
                 if res.GetChain() != config.INTRA:
                     continue
             a_contributing = []
             a_contributing_orig_idx = []
-            if res.GetName() in ('ARG', 'HIS', 'LYS'):  # Arginine, Histidine or Lysine have charged sidechains
+            if res.GetName() in (
+                "ARG",
+                "HIS",
+                "LYS",
+            ):  # Arginine, Histidine or Lysine have charged sidechains
                 for a in pybel.ob.OBResidueAtomIter(res):
-                    if a.GetType().startswith('N') and res.GetAtomProperty(a, 8) \
-                            and not self.Mapper.mapid(a.GetIdx(), mtype='protein') in self.altconf:
+                    if (
+                        a.GetType().startswith("N")
+                        and res.GetAtomProperty(a, 8)
+                        and not self.Mapper.mapid(a.GetIdx(), mtype="protein")
+                        in self.altconf
+                    ):
                         a_contributing.append(pybel.Atom(a))
-                        a_contributing_orig_idx.append(self.Mapper.mapid(a.GetIdx(), mtype='protein'))
+                        a_contributing_orig_idx.append(
+                            self.Mapper.mapid(a.GetIdx(), mtype="protein")
+                        )
                 if not len(a_contributing) == 0:
-                    a_set.append(data(atoms=a_contributing,
-                                      atoms_orig_idx=a_contributing_orig_idx,
-                                      type='positive',
-                                      center=centroid([ac.coords for ac in a_contributing]),
-                                      restype=res.GetName(),
-                                      resnr=res.GetNum(),
-                                      reschain=res.GetChain()))
-            if res.GetName() in ('GLU', 'ASP'):  # Aspartic or Glutamic Acid
+                    a_set.append(
+                        data(
+                            atoms=a_contributing,
+                            atoms_orig_idx=a_contributing_orig_idx,
+                            type="positive",
+                            center=centroid([ac.coords for ac in a_contributing]),
+                            restype=res.GetName(),
+                            resnr=res.GetNum(),
+                            reschain=res.GetChain(),
+                        )
+                    )
+            if res.GetName() in ("GLU", "ASP"):  # Aspartic or Glutamic Acid
                 for a in pybel.ob.OBResidueAtomIter(res):
-                    if a.GetType().startswith('O') and res.GetAtomProperty(a, 8) \
-                            and not self.Mapper.mapid(a.GetIdx(), mtype='protein') in self.altconf:
+                    if (
+                        a.GetType().startswith("O")
+                        and res.GetAtomProperty(a, 8)
+                        and not self.Mapper.mapid(a.GetIdx(), mtype="protein")
+                        in self.altconf
+                    ):
                         a_contributing.append(pybel.Atom(a))
-                        a_contributing_orig_idx.append(self.Mapper.mapid(a.GetIdx(), mtype='protein'))
+                        a_contributing_orig_idx.append(
+                            self.Mapper.mapid(a.GetIdx(), mtype="protein")
+                        )
                 if not len(a_contributing) == 0:
-                    a_set.append(data(atoms=a_contributing,
-                                      atoms_orig_idx=a_contributing_orig_idx,
-                                      type='negative',
-                                      center=centroid([ac.coords for ac in a_contributing]),
-                                      restype=res.GetName(),
-                                      resnr=res.GetNum(),
-                                      reschain=res.GetChain()))
+                    a_set.append(
+                        data(
+                            atoms=a_contributing,
+                            atoms_orig_idx=a_contributing_orig_idx,
+                            type="negative",
+                            center=centroid([ac.coords for ac in a_contributing]),
+                            restype=res.GetName(),
+                            resnr=res.GetNum(),
+                            reschain=res.GetChain(),
+                        )
+                    )
         return a_set
 
     def find_metal_binding(self, mol):
         """Looks for atoms that could possibly be involved in chelating a metal ion.
         This can be any main chain oxygen atom or oxygen, nitrogen and sulfur from specific amino acids"""
-        data = namedtuple('metal_binding', 'atom atom_orig_idx type restype resnr reschain location')
+        data = namedtuple(
+            "metal_binding", "atom atom_orig_idx type restype resnr reschain location"
+        )
         a_set = []
         for res in pybel.ob.OBResidueIter(mol.OBMol):
-            restype, reschain, resnr = res.GetName().upper(), res.GetChain(), res.GetNum()
-            if restype in ['ASP', 'GLU', 'SER', 'THR', 'TYR']:  # Look for oxygens here
+            restype, reschain, resnr = (
+                res.GetName().upper(),
+                res.GetChain(),
+                res.GetNum(),
+            )
+            if restype in ["ASP", "GLU", "SER", "THR", "TYR"]:  # Look for oxygens here
                 for a in pybel.ob.OBResidueAtomIter(res):
-                    if a.GetType().startswith('O') and res.GetAtomProperty(a, 8) \
-                            and not self.Mapper.mapid(a.GetIdx(), mtype='protein') in self.altconf:
-                        atom_orig_idx = self.Mapper.mapid(a.GetIdx(), mtype=self.mtype, bsid=self.bsid)
-                        a_set.append(data(atom=pybel.Atom(a), atom_orig_idx=atom_orig_idx, type='O', restype=restype,
-                                          resnr=resnr, reschain=reschain,
-                                          location='protein.sidechain'))
-            if restype == 'HIS':  # Look for nitrogen here
+                    if (
+                        a.GetType().startswith("O")
+                        and res.GetAtomProperty(a, 8)
+                        and not self.Mapper.mapid(a.GetIdx(), mtype="protein")
+                        in self.altconf
+                    ):
+                        atom_orig_idx = self.Mapper.mapid(
+                            a.GetIdx(), mtype=self.mtype, bsid=self.bsid
+                        )
+                        a_set.append(
+                            data(
+                                atom=pybel.Atom(a),
+                                atom_orig_idx=atom_orig_idx,
+                                type="O",
+                                restype=restype,
+                                resnr=resnr,
+                                reschain=reschain,
+                                location="protein.sidechain",
+                            )
+                        )
+            if restype == "HIS":  # Look for nitrogen here
                 for a in pybel.ob.OBResidueAtomIter(res):
-                    if a.GetType().startswith('N') and res.GetAtomProperty(a, 8) \
-                            and not self.Mapper.mapid(a.GetIdx(), mtype='protein') in self.altconf:
-                        atom_orig_idx = self.Mapper.mapid(a.GetIdx(), mtype=self.mtype, bsid=self.bsid)
-                        a_set.append(data(atom=pybel.Atom(a), atom_orig_idx=atom_orig_idx, type='N', restype=restype,
-                                          resnr=resnr, reschain=reschain,
-                                          location='protein.sidechain'))
-            if restype == 'CYS':  # Look for sulfur here
+                    if (
+                        a.GetType().startswith("N")
+                        and res.GetAtomProperty(a, 8)
+                        and not self.Mapper.mapid(a.GetIdx(), mtype="protein")
+                        in self.altconf
+                    ):
+                        atom_orig_idx = self.Mapper.mapid(
+                            a.GetIdx(), mtype=self.mtype, bsid=self.bsid
+                        )
+                        a_set.append(
+                            data(
+                                atom=pybel.Atom(a),
+                                atom_orig_idx=atom_orig_idx,
+                                type="N",
+                                restype=restype,
+                                resnr=resnr,
+                                reschain=reschain,
+                                location="protein.sidechain",
+                            )
+                        )
+            if restype == "CYS":  # Look for sulfur here
                 for a in pybel.ob.OBResidueAtomIter(res):
-                    if a.GetType().startswith('S') and res.GetAtomProperty(a, 8) \
-                            and not self.Mapper.mapid(a.GetIdx(), mtype='protein') in self.altconf:
-                        atom_orig_idx = self.Mapper.mapid(a.GetIdx(), mtype=self.mtype, bsid=self.bsid)
-                        a_set.append(data(atom=pybel.Atom(a), atom_orig_idx=atom_orig_idx, type='S', restype=restype,
-                                          resnr=resnr, reschain=reschain,
-                                          location='protein.sidechain'))
+                    if (
+                        a.GetType().startswith("S")
+                        and res.GetAtomProperty(a, 8)
+                        and not self.Mapper.mapid(a.GetIdx(), mtype="protein")
+                        in self.altconf
+                    ):
+                        atom_orig_idx = self.Mapper.mapid(
+                            a.GetIdx(), mtype=self.mtype, bsid=self.bsid
+                        )
+                        a_set.append(
+                            data(
+                                atom=pybel.Atom(a),
+                                atom_orig_idx=atom_orig_idx,
+                                type="S",
+                                restype=restype,
+                                resnr=resnr,
+                                reschain=reschain,
+                                location="protein.sidechain",
+                            )
+                        )
             for a in pybel.ob.OBResidueAtomIter(res):  # All main chain oxygens
-                if a.GetType().startswith('O') and res.GetAtomProperty(a, 2) \
-                        and not self.Mapper.mapid(a.GetIdx(), mtype='protein') in self.altconf and restype != 'HOH':
-                    atom_orig_idx = self.Mapper.mapid(a.GetIdx(), mtype=self.mtype, bsid=self.bsid)
-                    a_set.append(data(atom=pybel.Atom(a), atom_orig_idx=atom_orig_idx, type='O', restype=res.GetName(),
-                                      resnr=res.GetNum(), reschain=res.GetChain(),
-                                      location='protein.mainchain'))
+                if (
+                    a.GetType().startswith("O")
+                    and res.GetAtomProperty(a, 2)
+                    and not self.Mapper.mapid(a.GetIdx(), mtype="protein")
+                    in self.altconf
+                    and restype != "HOH"
+                ):
+                    atom_orig_idx = self.Mapper.mapid(
+                        a.GetIdx(), mtype=self.mtype, bsid=self.bsid
+                    )
+                    a_set.append(
+                        data(
+                            atom=pybel.Atom(a),
+                            atom_orig_idx=atom_orig_idx,
+                            type="O",
+                            restype=res.GetName(),
+                            resnr=res.GetNum(),
+                            reschain=res.GetChain(),
+                            location="protein.mainchain",
+                        )
+                    )
         return a_set
 
 
 class Ligand(Mol):
     def __init__(self, cclass, ligand):
         altconf = cclass.altconf
-        self.hetid, self.chain, self.position = ligand.hetid, ligand.chain, ligand.position
-        self.bsid = ':'.join([self.hetid, self.chain, str(self.position)])
-        Mol.__init__(self, altconf, cclass.Mapper, mtype='ligand', bsid=self.bsid)
+        self.hetid, self.chain, self.position = (
+            ligand.hetid,
+            ligand.chain,
+            ligand.position,
+        )
+        self.bsid = ":".join([self.hetid, self.chain, str(self.position)])
+        Mol.__init__(self, altconf, cclass.Mapper, mtype="ligand", bsid=self.bsid)
         self.members = ligand.members
         self.longname = ligand.longname
         self.type = ligand.type
         self.complex = cclass
         self.molecule = ligand.mol  # Pybel Molecule
-        self.smiles = self.molecule.write(format='can')  # SMILES String
-        self.inchikey = self.molecule.write(format='inchikey')
+        self.smiles = self.molecule.write(format="can")  # SMILES String
+        self.inchikey = self.molecule.write(format="inchikey")
         self.can_to_pdb = ligand.can_to_pdb
         if not len(self.smiles) == 0:
             self.smiles = self.smiles.split()[0]
         else:
-            logger.warning(f'could not write SMILES for ligand {ligand}')
-            self.smiles = ''
+            logger.warning(f"could not write SMILES for ligand {ligand}")
+            self.smiles = ""
         self.heavy_atoms = self.molecule.OBMol.NumHvyAtoms()  # Heavy atoms count
         self.all_atoms = self.molecule.atoms
         self.atmdict = {l.idx: l for l in self.all_atoms}
@@ -1007,9 +1482,9 @@ class Ligand(Mol):
         self.hbond_acc_atoms = self.find_hba(self.all_atoms)
         self.num_rings = len(self.rings)
         if self.num_rings != 0:
-            logger.info(f'contains {self.num_rings} aromatic ring(s)')
+            logger.info(f"contains {self.num_rings} aromatic ring(s)")
         descvalues = self.molecule.calcdesc()
-        self.molweight, self.logp = float(descvalues['MW']), float(descvalues['logP'])
+        self.molweight, self.logp = float(descvalues["MW"]), float(descvalues["logP"])
         self.num_rot_bonds = int(self.molecule.OBMol.NumRotors())
         self.atomorder = ligand.atomorder
 
@@ -1017,48 +1492,73 @@ class Ligand(Mol):
         # Special Case for hydrogen bond acceptor identification #
         ##########################################################
 
-        self.inverse_mapping = {v: k for k, v in self.Mapper.ligandmaps[self.bsid].items()}
+        self.inverse_mapping = {
+            v: k for k, v in self.Mapper.ligandmaps[self.bsid].items()
+        }
         self.pdb_to_idx_mapping = {v: k for k, v in self.Mapper.proteinmap.items()}
         self.hbond_don_atom_pairs = self.find_hbd(self.all_atoms, self.hydroph_atoms)
 
         ######
         donor_pairs = []
-        data = namedtuple('hbonddonor', 'd d_orig_atom d_orig_idx h type')
+        data = namedtuple("hbonddonor", "d d_orig_atom d_orig_idx h type")
         for donor in self.all_atoms:
-            pdbidx = self.Mapper.mapid(donor.idx, mtype='ligand', bsid=self.bsid, to='original')
+            pdbidx = self.Mapper.mapid(
+                donor.idx, mtype="ligand", bsid=self.bsid, to="original"
+            )
             d = cclass.atoms[self.pdb_to_idx_mapping[pdbidx]]
             if d.OBAtom.IsHbondDonor():
-                for adj_atom in [a for a in pybel.ob.OBAtomAtomIter(d.OBAtom) if a.IsHbondDonorH()]:
+                for adj_atom in [
+                    a for a in pybel.ob.OBAtomAtomIter(d.OBAtom) if a.IsHbondDonorH()
+                ]:
                     d_orig_atom = self.Mapper.id_to_atom(pdbidx)
-                    donor_pairs.append(data(d=donor, d_orig_atom=d_orig_atom, d_orig_idx=pdbidx,
-                                            h=pybel.Atom(adj_atom), type='regular'))
+                    donor_pairs.append(
+                        data(
+                            d=donor,
+                            d_orig_atom=d_orig_atom,
+                            d_orig_idx=pdbidx,
+                            h=pybel.Atom(adj_atom),
+                            type="regular",
+                        )
+                    )
         self.hbond_don_atom_pairs = donor_pairs
         #######
 
         self.charged = self.find_charged(self.all_atoms)
         self.centroid = centroid([a.coords for a in self.all_atoms])
-        self.max_dist_to_center = max((euclidean3d(self.centroid, a.coords) for a in self.all_atoms))
+        self.max_dist_to_center = max(
+            (euclidean3d(self.centroid, a.coords) for a in self.all_atoms)
+        )
         self.water = []
-        data = namedtuple('water', 'oxy oxy_orig_idx')
+        data = namedtuple("water", "oxy oxy_orig_idx")
         for hoh in ligand.water:
             oxy = None
             for at in pybel.ob.OBResidueAtomIter(hoh):
                 if at.GetAtomicNum() == 8 and at.GetIdx() not in self.altconf:
                     oxy = pybel.Atom(at)
             # There are some cases where there is no oxygen in a water residue, ignore those
-            if not set([at.GetAtomicNum() for at in pybel.ob.OBResidueAtomIter(hoh)]) == {1} and oxy is not None:
-                if euclidean3d(self.centroid, oxy.coords) < self.max_dist_to_center + config.BS_DIST:
-                    oxy_orig_idx = self.Mapper.mapid(oxy.idx, mtype='protein')
+            if (
+                not set([at.GetAtomicNum() for at in pybel.ob.OBResidueAtomIter(hoh)])
+                == {1}
+                and oxy is not None
+            ):
+                if (
+                    euclidean3d(self.centroid, oxy.coords)
+                    < self.max_dist_to_center + config.BS_DIST
+                ):
+                    oxy_orig_idx = self.Mapper.mapid(oxy.idx, mtype="protein")
                     self.water.append(data(oxy=oxy, oxy_orig_idx=oxy_orig_idx))
         self.halogenbond_don = self.find_hal(self.all_atoms)
         self.metal_binding = self.find_metal_binding(self.all_atoms, self.water)
         self.metals = []
-        data = namedtuple('metal', 'm orig_m m_orig_idx')
+        data = namedtuple("metal", "m orig_m m_orig_idx")
         for a in [a for a in self.all_atoms if a.type.upper() in config.METAL_IONS]:
             m_orig_idx = self.Mapper.mapid(a.idx, mtype=self.mtype, bsid=self.bsid)
             orig_m = self.Mapper.id_to_atom(m_orig_idx)
             self.metals.append(data(m=a, m_orig_idx=m_orig_idx, orig_m=orig_m))
-        self.num_hba, self.num_hbd = len(self.hbond_acc_atoms), len(self.hbond_don_atom_pairs)
+        self.num_hba, self.num_hbd = (
+            len(self.hbond_acc_atoms),
+            len(self.hbond_don_atom_pairs),
+        )
         self.num_hal = len(self.halogenbond_don)
 
     def get_canonical_num(self, atomnum):
@@ -1067,41 +1567,69 @@ class Ligand(Mol):
 
     def is_functional_group(self, atom, group):
         """Given a pybel atom, look up if it belongs to a function group"""
-        n_atoms = [a_neighbor.GetAtomicNum() for a_neighbor in pybel.ob.OBAtomAtomIter(atom.OBAtom)]
+        n_atoms = [
+            a_neighbor.GetAtomicNum()
+            for a_neighbor in pybel.ob.OBAtomAtomIter(atom.OBAtom)
+        ]
 
-        if group in ['quartamine', 'tertamine'] and atom.atomicnum == 7:  # Nitrogen
+        if group in ["quartamine", "tertamine"] and atom.atomicnum == 7:  # Nitrogen
             # It's a nitrogen, so could be a protonated amine or quaternary ammonium
-            if '1' not in n_atoms and len(n_atoms) == 4:
-                return True if group == 'quartamine' else False  # It's a quat. ammonium (N with 4 residues != H)
+            if "1" not in n_atoms and len(n_atoms) == 4:
+                return (
+                    True if group == "quartamine" else False
+                )  # It's a quat. ammonium (N with 4 residues != H)
             elif atom.OBAtom.GetHyb() == 3 and len(n_atoms) >= 3:
-                return True if group == 'tertamine' else False  # It's sp3-hybridized, so could pick up an hydrogen
+                return (
+                    True if group == "tertamine" else False
+                )  # It's sp3-hybridized, so could pick up an hydrogen
             else:
                 return False
 
-        if group in ['sulfonium', 'sulfonicacid', 'sulfate'] and atom.atomicnum == 16:  # Sulfur
-            if '1' not in n_atoms and len(n_atoms) == 3:  # It's a sulfonium (S with 3 residues != H)
-                return True if group == 'sulfonium' else False
+        if (
+            group in ["sulfonium", "sulfonicacid", "sulfate"] and atom.atomicnum == 16
+        ):  # Sulfur
+            if (
+                "1" not in n_atoms and len(n_atoms) == 3
+            ):  # It's a sulfonium (S with 3 residues != H)
+                return True if group == "sulfonium" else False
             elif n_atoms.count(8) == 3:  # It's a sulfonate or sulfonic acid
-                return True if group == 'sulfonicacid' else False
+                return True if group == "sulfonicacid" else False
             elif n_atoms.count(8) == 4:  # It's a sulfate
-                return True if group == 'sulfate' else False
+                return True if group == "sulfate" else False
 
-        if group == 'phosphate' and atom.atomicnum == 15:  # Phosphor
+        if group == "phosphate" and atom.atomicnum == 15:  # Phosphor
             if set(n_atoms) == {8}:  # It's a phosphate
                 return True
 
-        if group in ['carboxylate', 'guanidine'] and atom.atomicnum == 6:  # It's a carbon atom
-            if n_atoms.count(8) == 2 and n_atoms.count(6) == 1:  # It's a carboxylate group
-                return True if group == 'carboxylate' else False
+        if (
+            group in ["carboxylate", "guanidine"] and atom.atomicnum == 6
+        ):  # It's a carbon atom
+            if (
+                n_atoms.count(8) == 2 and n_atoms.count(6) == 1
+            ):  # It's a carboxylate group
+                return True if group == "carboxylate" else False
             elif n_atoms.count(7) == 3 and len(n_atoms) == 3:  # It's a guanidine group
                 nitro_partners = []
                 for nitro in pybel.ob.OBAtomAtomIter(atom.OBAtom):
-                    nitro_partners.append(len([b_neighbor for b_neighbor in pybel.ob.OBAtomAtomIter(nitro)]))
-                if min(nitro_partners) == 1:  # One nitrogen is only connected to the carbon, can pick up a H
-                    return True if group == 'guanidine' else False
-
-        if group == 'halocarbon' and atom.atomicnum in [9, 17, 35, 53]:  # Halogen atoms
-            n_atoms = [na for na in pybel.ob.OBAtomAtomIter(atom.OBAtom) if na.GetAtomicNum() == 6]
+                    nitro_partners.append(
+                        len(
+                            [
+                                b_neighbor
+                                for b_neighbor in pybel.ob.OBAtomAtomIter(nitro)
+                            ]
+                        )
+                    )
+                if (
+                    min(nitro_partners) == 1
+                ):  # One nitrogen is only connected to the carbon, can pick up a H
+                    return True if group == "guanidine" else False
+
+        if group == "halocarbon" and atom.atomicnum in [9, 17, 35, 53]:  # Halogen atoms
+            n_atoms = [
+                na
+                for na in pybel.ob.OBAtomAtomIter(atom.OBAtom)
+                if na.GetAtomicNum() == 6
+            ]
             if len(n_atoms) == 1:  # Halocarbon
                 return True
         else:
@@ -1109,18 +1637,32 @@ class Ligand(Mol):
 
     def find_hal(self, atoms):
         """Look for halogen bond donors (X-C, with X=F, Cl, Br, I)"""
-        data = namedtuple('hal_donor', 'x orig_x x_orig_idx c c_orig_idx')
+        data = namedtuple("hal_donor", "x orig_x x_orig_idx c c_orig_idx")
         a_set = []
         for a in atoms:
-            if self.is_functional_group(a, 'halocarbon'):
-                n_atoms = [na for na in pybel.ob.OBAtomAtomIter(a.OBAtom) if na.GetAtomicNum() == 6]
+            if self.is_functional_group(a, "halocarbon"):
+                n_atoms = [
+                    na
+                    for na in pybel.ob.OBAtomAtomIter(a.OBAtom)
+                    if na.GetAtomicNum() == 6
+                ]
                 x_orig_idx = self.Mapper.mapid(a.idx, mtype=self.mtype, bsid=self.bsid)
                 orig_x = self.Mapper.id_to_atom(x_orig_idx)
-                c_orig_idx = [self.Mapper.mapid(na.GetIdx(), mtype=self.mtype, bsid=self.bsid) for na in n_atoms]
-                a_set.append(data(x=a, orig_x=orig_x, x_orig_idx=x_orig_idx,
-                                  c=pybel.Atom(n_atoms[0]), c_orig_idx=c_orig_idx))
+                c_orig_idx = [
+                    self.Mapper.mapid(na.GetIdx(), mtype=self.mtype, bsid=self.bsid)
+                    for na in n_atoms
+                ]
+                a_set.append(
+                    data(
+                        x=a,
+                        orig_x=orig_x,
+                        x_orig_idx=x_orig_idx,
+                        c=pybel.Atom(n_atoms[0]),
+                        c_orig_idx=c_orig_idx,
+                    )
+                )
         if len(a_set) != 0:
-            logger.info(f'ligand contains {len(a_set)} halogen atom(s)')
+            logger.info(f"ligand contains {len(a_set)} halogen atom(s)")
         return a_set
 
     def find_charged(self, all_atoms):
@@ -1129,76 +1671,189 @@ class Ligand(Mol):
         as mentioned in 'Cation-pi interactions in ligand recognition and catalysis' (Zacharias et al., 2002)).
         Identify negatively charged groups in the ligand.
         """
-        data = namedtuple('lcharge', 'atoms orig_atoms atoms_orig_idx type center fgroup')
+        data = namedtuple(
+            "lcharge", "atoms orig_atoms atoms_orig_idx type center fgroup"
+        )
         a_set = []
         for a in all_atoms:
             a_orig_idx = self.Mapper.mapid(a.idx, mtype=self.mtype, bsid=self.bsid)
             a_orig = self.Mapper.id_to_atom(a_orig_idx)
-            if self.is_functional_group(a, 'quartamine'):
-                a_set.append(data(atoms=[a, ], orig_atoms=[a_orig, ], atoms_orig_idx=[a_orig_idx, ], type='positive',
-                                  center=list(a.coords), fgroup='quartamine'))
-            elif self.is_functional_group(a, 'tertamine'):
-                a_set.append(data(atoms=[a, ], orig_atoms=[a_orig, ], atoms_orig_idx=[a_orig_idx, ], type='positive',
-                                  center=list(a.coords),
-                                  fgroup='tertamine'))
-            if self.is_functional_group(a, 'sulfonium'):
-                a_set.append(data(atoms=[a, ], orig_atoms=[a_orig, ], atoms_orig_idx=[a_orig_idx, ], type='positive',
-                                  center=list(a.coords),
-                                  fgroup='sulfonium'))
-            if self.is_functional_group(a, 'phosphate'):
-                a_contributing = [a, ]
-                a_contributing_orig_idx = [a_orig_idx, ]
-                [a_contributing.append(pybel.Atom(neighbor)) for neighbor in pybel.ob.OBAtomAtomIter(a.OBAtom)]
-                [a_contributing_orig_idx.append(self.Mapper.mapid(neighbor.idx, mtype=self.mtype, bsid=self.bsid))
-                 for neighbor in a_contributing]
-                orig_contributing = [self.Mapper.id_to_atom(idx) for idx in a_contributing_orig_idx]
+            if self.is_functional_group(a, "quartamine"):
+                a_set.append(
+                    data(
+                        atoms=[a,],
+                        orig_atoms=[a_orig,],
+                        atoms_orig_idx=[a_orig_idx,],
+                        type="positive",
+                        center=list(a.coords),
+                        fgroup="quartamine",
+                    )
+                )
+            elif self.is_functional_group(a, "tertamine"):
                 a_set.append(
-                    data(atoms=a_contributing, orig_atoms=orig_contributing, atoms_orig_idx=a_contributing_orig_idx,
-                         type='negative',
-                         center=a.coords, fgroup='phosphate'))
-            if self.is_functional_group(a, 'sulfonicacid'):
-                a_contributing = [a, ]
-                a_contributing_orig_idx = [a_orig_idx, ]
-                [a_contributing.append(pybel.Atom(neighbor)) for neighbor in pybel.ob.OBAtomAtomIter(a.OBAtom) if
-                 neighbor.GetAtomicNum() == 8]
-                [a_contributing_orig_idx.append(self.Mapper.mapid(neighbor.idx, mtype=self.mtype, bsid=self.bsid))
-                 for neighbor in a_contributing]
-                orig_contributing = [self.Mapper.id_to_atom(idx) for idx in a_contributing_orig_idx]
+                    data(
+                        atoms=[a,],
+                        orig_atoms=[a_orig,],
+                        atoms_orig_idx=[a_orig_idx,],
+                        type="positive",
+                        center=list(a.coords),
+                        fgroup="tertamine",
+                    )
+                )
+            if self.is_functional_group(a, "sulfonium"):
                 a_set.append(
-                    data(atoms=a_contributing, orig_atoms=orig_contributing, atoms_orig_idx=a_contributing_orig_idx,
-                         type='negative',
-                         center=a.coords, fgroup='sulfonicacid'))
-            elif self.is_functional_group(a, 'sulfate'):
-                a_contributing = [a, ]
-                a_contributing_orig_idx = [a_orig_idx, ]
-                [a_contributing_orig_idx.append(self.Mapper.mapid(neighbor.idx, mtype=self.mtype, bsid=self.bsid))
-                 for neighbor in a_contributing]
-                [a_contributing.append(pybel.Atom(neighbor)) for neighbor in pybel.ob.OBAtomAtomIter(a.OBAtom)]
-                orig_contributing = [self.Mapper.id_to_atom(idx) for idx in a_contributing_orig_idx]
+                    data(
+                        atoms=[a,],
+                        orig_atoms=[a_orig,],
+                        atoms_orig_idx=[a_orig_idx,],
+                        type="positive",
+                        center=list(a.coords),
+                        fgroup="sulfonium",
+                    )
+                )
+            if self.is_functional_group(a, "phosphate"):
+                a_contributing = [
+                    a,
+                ]
+                a_contributing_orig_idx = [
+                    a_orig_idx,
+                ]
+                [
+                    a_contributing.append(pybel.Atom(neighbor))
+                    for neighbor in pybel.ob.OBAtomAtomIter(a.OBAtom)
+                ]
+                [
+                    a_contributing_orig_idx.append(
+                        self.Mapper.mapid(
+                            neighbor.idx, mtype=self.mtype, bsid=self.bsid
+                        )
+                    )
+                    for neighbor in a_contributing
+                ]
+                orig_contributing = [
+                    self.Mapper.id_to_atom(idx) for idx in a_contributing_orig_idx
+                ]
                 a_set.append(
-                    data(atoms=a_contributing, orig_atoms=orig_contributing, atoms_orig_idx=a_contributing_orig_idx,
-                         type='negative',
-                         center=a.coords, fgroup='sulfate'))
-            if self.is_functional_group(a, 'carboxylate'):
-                a_contributing = [pybel.Atom(neighbor) for neighbor in pybel.ob.OBAtomAtomIter(a.OBAtom)
-                                  if neighbor.GetAtomicNum() == 8]
-                a_contributing_orig_idx = [self.Mapper.mapid(neighbor.idx, mtype=self.mtype, bsid=self.bsid)
-                                           for neighbor in a_contributing]
-                orig_contributing = [self.Mapper.id_to_atom(idx) for idx in a_contributing_orig_idx]
+                    data(
+                        atoms=a_contributing,
+                        orig_atoms=orig_contributing,
+                        atoms_orig_idx=a_contributing_orig_idx,
+                        type="negative",
+                        center=a.coords,
+                        fgroup="phosphate",
+                    )
+                )
+            if self.is_functional_group(a, "sulfonicacid"):
+                a_contributing = [
+                    a,
+                ]
+                a_contributing_orig_idx = [
+                    a_orig_idx,
+                ]
+                [
+                    a_contributing.append(pybel.Atom(neighbor))
+                    for neighbor in pybel.ob.OBAtomAtomIter(a.OBAtom)
+                    if neighbor.GetAtomicNum() == 8
+                ]
+                [
+                    a_contributing_orig_idx.append(
+                        self.Mapper.mapid(
+                            neighbor.idx, mtype=self.mtype, bsid=self.bsid
+                        )
+                    )
+                    for neighbor in a_contributing
+                ]
+                orig_contributing = [
+                    self.Mapper.id_to_atom(idx) for idx in a_contributing_orig_idx
+                ]
                 a_set.append(
-                    data(atoms=a_contributing, orig_atoms=orig_contributing, atoms_orig_idx=a_contributing_orig_idx,
-                         type='negative',
-                         center=centroid([a.coords for a in a_contributing]), fgroup='carboxylate'))
-            elif self.is_functional_group(a, 'guanidine'):
-                a_contributing = [pybel.Atom(neighbor) for neighbor in pybel.ob.OBAtomAtomIter(a.OBAtom)
-                                  if neighbor.GetAtomicNum() == 7]
-                a_contributing_orig_idx = [self.Mapper.mapid(neighbor.idx, mtype=self.mtype, bsid=self.bsid)
-                                           for neighbor in a_contributing]
-                orig_contributing = [self.Mapper.id_to_atom(idx) for idx in a_contributing_orig_idx]
+                    data(
+                        atoms=a_contributing,
+                        orig_atoms=orig_contributing,
+                        atoms_orig_idx=a_contributing_orig_idx,
+                        type="negative",
+                        center=a.coords,
+                        fgroup="sulfonicacid",
+                    )
+                )
+            elif self.is_functional_group(a, "sulfate"):
+                a_contributing = [
+                    a,
+                ]
+                a_contributing_orig_idx = [
+                    a_orig_idx,
+                ]
+                [
+                    a_contributing_orig_idx.append(
+                        self.Mapper.mapid(
+                            neighbor.idx, mtype=self.mtype, bsid=self.bsid
+                        )
+                    )
+                    for neighbor in a_contributing
+                ]
+                [
+                    a_contributing.append(pybel.Atom(neighbor))
+                    for neighbor in pybel.ob.OBAtomAtomIter(a.OBAtom)
+                ]
+                orig_contributing = [
+                    self.Mapper.id_to_atom(idx) for idx in a_contributing_orig_idx
+                ]
                 a_set.append(
-                    data(atoms=a_contributing, orig_atoms=orig_contributing, atoms_orig_idx=a_contributing_orig_idx,
-                         type='positive',
-                         center=a.coords, fgroup='guanidine'))
+                    data(
+                        atoms=a_contributing,
+                        orig_atoms=orig_contributing,
+                        atoms_orig_idx=a_contributing_orig_idx,
+                        type="negative",
+                        center=a.coords,
+                        fgroup="sulfate",
+                    )
+                )
+            if self.is_functional_group(a, "carboxylate"):
+                a_contributing = [
+                    pybel.Atom(neighbor)
+                    for neighbor in pybel.ob.OBAtomAtomIter(a.OBAtom)
+                    if neighbor.GetAtomicNum() == 8
+                ]
+                a_contributing_orig_idx = [
+                    self.Mapper.mapid(neighbor.idx, mtype=self.mtype, bsid=self.bsid)
+                    for neighbor in a_contributing
+                ]
+                orig_contributing = [
+                    self.Mapper.id_to_atom(idx) for idx in a_contributing_orig_idx
+                ]
+                a_set.append(
+                    data(
+                        atoms=a_contributing,
+                        orig_atoms=orig_contributing,
+                        atoms_orig_idx=a_contributing_orig_idx,
+                        type="negative",
+                        center=centroid([a.coords for a in a_contributing]),
+                        fgroup="carboxylate",
+                    )
+                )
+            elif self.is_functional_group(a, "guanidine"):
+                a_contributing = [
+                    pybel.Atom(neighbor)
+                    for neighbor in pybel.ob.OBAtomAtomIter(a.OBAtom)
+                    if neighbor.GetAtomicNum() == 7
+                ]
+                a_contributing_orig_idx = [
+                    self.Mapper.mapid(neighbor.idx, mtype=self.mtype, bsid=self.bsid)
+                    for neighbor in a_contributing
+                ]
+                orig_contributing = [
+                    self.Mapper.id_to_atom(idx) for idx in a_contributing_orig_idx
+                ]
+                a_set.append(
+                    data(
+                        atoms=a_contributing,
+                        orig_atoms=orig_contributing,
+                        atoms_orig_idx=a_contributing_orig_idx,
+                        type="positive",
+                        center=a.coords,
+                        fgroup="guanidine",
+                    )
+                )
         return a_set
 
     def find_metal_binding(self, lig_atoms, water_oxygens):
@@ -1207,67 +1862,173 @@ class Ligand(Mol):
         nitrogen from imidazole; sulfur from thiolate.
         """
         a_set = []
-        data = namedtuple('metal_binding', 'atom orig_atom atom_orig_idx type fgroup restype resnr reschain location')
+        data = namedtuple(
+            "metal_binding",
+            "atom orig_atom atom_orig_idx type fgroup restype resnr reschain location",
+        )
         for oxygen in water_oxygens:
-            a_set.append(data(atom=oxygen.oxy, atom_orig_idx=oxygen.oxy_orig_idx, type='O', fgroup='water',
-                              restype=whichrestype(oxygen.oxy), resnr=whichresnumber(oxygen.oxy),
-                              reschain=whichchain(oxygen.oxy), location='water',
-                              orig_atom=self.Mapper.id_to_atom(oxygen.oxy_orig_idx)))
+            a_set.append(
+                data(
+                    atom=oxygen.oxy,
+                    atom_orig_idx=oxygen.oxy_orig_idx,
+                    type="O",
+                    fgroup="water",
+                    restype=whichrestype(oxygen.oxy),
+                    resnr=whichresnumber(oxygen.oxy),
+                    reschain=whichchain(oxygen.oxy),
+                    location="water",
+                    orig_atom=self.Mapper.id_to_atom(oxygen.oxy_orig_idx),
+                )
+            )
         # #@todo Refactor code
         for a in lig_atoms:
-            a_orig_idx = self.Mapper.mapid(a.idx, mtype='ligand', bsid=self.bsid)
+            a_orig_idx = self.Mapper.mapid(a.idx, mtype="ligand", bsid=self.bsid)
             n_atoms = pybel.ob.OBAtomAtomIter(a.OBAtom)  # Neighboring atoms
             # All atomic numbers of neighboring atoms
-            n_atoms_atomicnum = [n.GetAtomicNum() for n in pybel.ob.OBAtomAtomIter(a.OBAtom)]
+            n_atoms_atomicnum = [
+                n.GetAtomicNum() for n in pybel.ob.OBAtomAtomIter(a.OBAtom)
+            ]
             if a.atomicnum == 8:  # Oxygen
-                if n_atoms_atomicnum.count('1') == 1 and len(n_atoms_atomicnum) == 2:  # Oxygen in alcohol (R-[O]-H)
-                    a_set.append(data(atom=a, atom_orig_idx=a_orig_idx, type='O', fgroup='alcohol',
-                                      restype=self.hetid, resnr=self.position, reschain=self.chain,
-                                      location='ligand', orig_atom=self.Mapper.id_to_atom(a_orig_idx)))
-                if True in [n.IsAromatic() for n in n_atoms] and not a.OBAtom.IsAromatic():  # Phenolate oxygen
-                    a_set.append(data(atom=a, atom_orig_idx=a_orig_idx, type='O', fgroup='phenolate',
-                                      restype=self.hetid, resnr=self.position, reschain=self.chain,
-                                      location='ligand', orig_atom=self.Mapper.id_to_atom(a_orig_idx)))
+                if (
+                    n_atoms_atomicnum.count("1") == 1 and len(n_atoms_atomicnum) == 2
+                ):  # Oxygen in alcohol (R-[O]-H)
+                    a_set.append(
+                        data(
+                            atom=a,
+                            atom_orig_idx=a_orig_idx,
+                            type="O",
+                            fgroup="alcohol",
+                            restype=self.hetid,
+                            resnr=self.position,
+                            reschain=self.chain,
+                            location="ligand",
+                            orig_atom=self.Mapper.id_to_atom(a_orig_idx),
+                        )
+                    )
+                if (
+                    True in [n.IsAromatic() for n in n_atoms]
+                    and not a.OBAtom.IsAromatic()
+                ):  # Phenolate oxygen
+                    a_set.append(
+                        data(
+                            atom=a,
+                            atom_orig_idx=a_orig_idx,
+                            type="O",
+                            fgroup="phenolate",
+                            restype=self.hetid,
+                            resnr=self.position,
+                            reschain=self.chain,
+                            location="ligand",
+                            orig_atom=self.Mapper.id_to_atom(a_orig_idx),
+                        )
+                    )
             if a.atomicnum == 6:  # It's a carbon atom
-                if n_atoms_atomicnum.count(8) == 2 and n_atoms_atomicnum.count(6) == 1:  # It's a carboxylate group
+                if (
+                    n_atoms_atomicnum.count(8) == 2 and n_atoms_atomicnum.count(6) == 1
+                ):  # It's a carboxylate group
                     for neighbor in [n for n in n_atoms if n.GetAtomicNum() == 8]:
-                        neighbor_orig_idx = self.Mapper.mapid(neighbor.GetIdx(), mtype='ligand', bsid=self.bsid)
-                        a_set.append(data(atom=pybel.Atom(neighbor), atom_orig_idx=neighbor_orig_idx, type='O',
-                                          fgroup='carboxylate',
-                                          restype=self.hetid,
-                                          resnr=self.position, reschain=self.chain,
-                                          location='ligand', orig_atom=self.Mapper.id_to_atom(a_orig_idx)))
+                        neighbor_orig_idx = self.Mapper.mapid(
+                            neighbor.GetIdx(), mtype="ligand", bsid=self.bsid
+                        )
+                        a_set.append(
+                            data(
+                                atom=pybel.Atom(neighbor),
+                                atom_orig_idx=neighbor_orig_idx,
+                                type="O",
+                                fgroup="carboxylate",
+                                restype=self.hetid,
+                                resnr=self.position,
+                                reschain=self.chain,
+                                location="ligand",
+                                orig_atom=self.Mapper.id_to_atom(a_orig_idx),
+                            )
+                        )
             if a.atomicnum == 15:  # It's a phosphor atom
                 if n_atoms_atomicnum.count(8) >= 3:  # It's a phosphoryl
                     for neighbor in [n for n in n_atoms if n.GetAtomicNum() == 8]:
-                        neighbor_orig_idx = self.Mapper.mapid(neighbor.GetIdx(), mtype='ligand', bsid=self.bsid)
-                        a_set.append(data(atom=pybel.Atom(neighbor), atom_orig_idx=neighbor_orig_idx, type='O',
-                                          fgroup='phosphoryl',
-                                          restype=self.hetid,
-                                          resnr=self.position, reschain=self.chain,
-                                          location='ligand', orig_atom=self.Mapper.id_to_atom(a_orig_idx)))
-                if n_atoms_atomicnum.count(8) == 2:  # It's another phosphor-containing group #@todo (correct name?)
+                        neighbor_orig_idx = self.Mapper.mapid(
+                            neighbor.GetIdx(), mtype="ligand", bsid=self.bsid
+                        )
+                        a_set.append(
+                            data(
+                                atom=pybel.Atom(neighbor),
+                                atom_orig_idx=neighbor_orig_idx,
+                                type="O",
+                                fgroup="phosphoryl",
+                                restype=self.hetid,
+                                resnr=self.position,
+                                reschain=self.chain,
+                                location="ligand",
+                                orig_atom=self.Mapper.id_to_atom(a_orig_idx),
+                            )
+                        )
+                if (
+                    n_atoms_atomicnum.count(8) == 2
+                ):  # It's another phosphor-containing group #@todo (correct name?)
                     for neighbor in [n for n in n_atoms if n.GetAtomicNum() == 8]:
-                        neighbor_orig_idx = self.Mapper.mapid(neighbor.GetIdx(), mtype='ligand', bsid=self.bsid)
-                        a_set.append(data(atom=pybel.Atom(neighbor), atom_orig_idx=neighbor_orig_idx, type='O',
-                                          fgroup='phosphor.other', restype=self.hetid,
-                                          resnr=self.position,
-                                          reschain=self.chain, location='ligand',
-                                          orig_atom=self.Mapper.id_to_atom(a_orig_idx)))
+                        neighbor_orig_idx = self.Mapper.mapid(
+                            neighbor.GetIdx(), mtype="ligand", bsid=self.bsid
+                        )
+                        a_set.append(
+                            data(
+                                atom=pybel.Atom(neighbor),
+                                atom_orig_idx=neighbor_orig_idx,
+                                type="O",
+                                fgroup="phosphor.other",
+                                restype=self.hetid,
+                                resnr=self.position,
+                                reschain=self.chain,
+                                location="ligand",
+                                orig_atom=self.Mapper.id_to_atom(a_orig_idx),
+                            )
+                        )
             if a.atomicnum == 7:  # It's a nitrogen atom
                 if n_atoms_atomicnum.count(6) == 2:  # It's imidazole/pyrrole or similar
-                    a_set.append(data(atom=a, atom_orig_idx=a_orig_idx, type='N', fgroup='imidazole/pyrrole',
-                                      restype=self.hetid, resnr=self.position, reschain=self.chain,
-                                      location='ligand', orig_atom=self.Mapper.id_to_atom(a_orig_idx)))
+                    a_set.append(
+                        data(
+                            atom=a,
+                            atom_orig_idx=a_orig_idx,
+                            type="N",
+                            fgroup="imidazole/pyrrole",
+                            restype=self.hetid,
+                            resnr=self.position,
+                            reschain=self.chain,
+                            location="ligand",
+                            orig_atom=self.Mapper.id_to_atom(a_orig_idx),
+                        )
+                    )
             if a.atomicnum == 16:  # It's a sulfur atom
-                if True in [n.IsAromatic() for n in n_atoms] and not a.OBAtom.IsAromatic():  # Thiolate
-                    a_set.append(data(atom=a, atom_orig_idx=a_orig_idx, type='S', fgroup='thiolate',
-                                      restype=self.hetid, resnr=self.position, reschain=self.chain,
-                                      location='ligand', orig_atom=self.Mapper.id_to_atom(a_orig_idx)))
+                if (
+                    True in [n.IsAromatic() for n in n_atoms]
+                    and not a.OBAtom.IsAromatic()
+                ):  # Thiolate
+                    a_set.append(
+                        data(
+                            atom=a,
+                            atom_orig_idx=a_orig_idx,
+                            type="S",
+                            fgroup="thiolate",
+                            restype=self.hetid,
+                            resnr=self.position,
+                            reschain=self.chain,
+                            location="ligand",
+                            orig_atom=self.Mapper.id_to_atom(a_orig_idx),
+                        )
+                    )
                 if set(n_atoms_atomicnum) == {26}:  # Sulfur in Iron sulfur cluster
-                    a_set.append(data(atom=a, atom_orig_idx=a_orig_idx, type='S', fgroup='iron-sulfur.cluster',
-                                      restype=self.hetid, resnr=self.position, reschain=self.chain,
-                                      location='ligand', orig_atom=self.Mapper.id_to_atom(a_orig_idx)))
+                    a_set.append(
+                        data(
+                            atom=a,
+                            atom_orig_idx=a_orig_idx,
+                            type="S",
+                            fgroup="iron-sulfur.cluster",
+                            restype=self.hetid,
+                            resnr=self.position,
+                            reschain=self.chain,
+                            location="ligand",
+                            orig_atom=self.Mapper.id_to_atom(a_orig_idx),
+                        )
+                    )
 
         return a_set
 
@@ -1279,43 +2040,54 @@ class PDBComplex:
     """
 
     def __init__(self):
-        self.interaction_sets = {}  # Dictionary with site identifiers as keys and object as value
+        self.interaction_sets = (
+            {}
+        )  # Dictionary with site identifiers as keys and object as value
         self.protcomplex = None
         self.filetype = None
         self.atoms = {}  # Dictionary of Pybel atoms, accessible by their idx
         self.sourcefiles = {}
         self.information = {}
-        self.corrected_pdb = ''
+        self.corrected_pdb = ""
         self._output_path = tempfile.gettempdir()
         self.pymol_name = None
         self.modres = set()
         self.resis = []
         self.altconf = []  # Atom idx of atoms with alternate conformations
-        self.covalent = []  # Covalent linkages between ligands and protein residues/other ligands
+        self.covalent = (
+            []
+        )  # Covalent linkages between ligands and protein residues/other ligands
         self.excluded = []  # Excluded ligands
         self.Mapper = Mapper()
         self.ligands = []
 
     def __str__(self):
-        formatted_lig_names = [":".join([x.hetid, x.chain, str(x.position)]) for x in self.ligands]
+        formatted_lig_names = [
+            ":".join([x.hetid, x.chain, str(x.position)]) for x in self.ligands
+        ]
         return "Protein structure %s with ligands:\n" % (self.pymol_name) + "\n".join(
-            [lig for lig in formatted_lig_names])
+            [lig for lig in formatted_lig_names]
+        )
 
     def load_pdb(self, pdbpath, as_string=False):
         """Loads a pdb file with protein AND ligand(s), separates and prepares them.
         If specified 'as_string', the input is a PDB string instead of a path."""
         if as_string:
-            self.sourcefiles['pdbcomplex.original'] = None
-            self.sourcefiles['pdbcomplex'] = None
-            self.sourcefiles['pdbstring'] = pdbpath
+            self.sourcefiles["pdbcomplex.original"] = None
+            self.sourcefiles["pdbcomplex"] = None
+            self.sourcefiles["pdbstring"] = pdbpath
         else:
-            self.sourcefiles['pdbcomplex.original'] = pdbpath
-            self.sourcefiles['pdbcomplex'] = pdbpath
-        self.information['pdbfixes'] = False
-        pdbparser = PDBParser(pdbpath, as_string=as_string)  # Parse PDB file to find errors and get additional data
+            self.sourcefiles["pdbcomplex.original"] = pdbpath
+            self.sourcefiles["pdbcomplex"] = pdbpath
+        self.information["pdbfixes"] = False
+        pdbparser = PDBParser(
+            pdbpath, as_string=as_string
+        )  # Parse PDB file to find errors and get additional data
         # #@todo Refactor and rename here
         self.Mapper.proteinmap = pdbparser.proteinmap
-        self.Mapper.reversed_proteinmap = {v: k for k, v in self.Mapper.proteinmap.items()}
+        self.Mapper.reversed_proteinmap = {
+            v: k for k, v in self.Mapper.proteinmap.items()
+        }
         self.modres = pdbparser.modres
         self.covalent = pdbparser.covalent
         self.altconf = pdbparser.altconformations
@@ -1323,78 +2095,103 @@ class PDBComplex:
 
         if not config.PLUGIN_MODE:
             if pdbparser.num_fixed_lines > 0:
-                logger.info(f'{pdbparser.num_fixed_lines} lines automatically fixed in PDB input file')
+                logger.info(
+                    f"{pdbparser.num_fixed_lines} lines automatically fixed in PDB input file"
+                )
                 # Save modified PDB file
                 if not as_string:
-                    basename = os.path.basename(pdbpath).split('.')[0]
+                    basename = os.path.basename(pdbpath).split(".")[0]
                 else:
                     basename = "from_stdin"
-                pdbpath_fixed = tmpfile(prefix='plipfixed.' + basename + '_', direc=self.output_path)
+                pdbpath_fixed = tmpfile(
+                    prefix="plipfixed." + basename + "_", direc=self.output_path
+                )
                 create_folder_if_not_exists(self.output_path)
-                self.sourcefiles['pdbcomplex'] = pdbpath_fixed
-                self.corrected_pdb = re.sub(r'[^\x00-\x7F]+', ' ', self.corrected_pdb)  # Strip non-unicode chars
-                if not config.NOFIXFILE:  # Only write to file if this option is not activated
-                    with open(pdbpath_fixed, 'w') as f:
+                self.sourcefiles["pdbcomplex"] = pdbpath_fixed
+                self.corrected_pdb = re.sub(
+                    r"[^\x00-\x7F]+", " ", self.corrected_pdb
+                )  # Strip non-unicode chars
+                if (
+                    not config.NOFIXFILE
+                ):  # Only write to file if this option is not activated
+                    with open(pdbpath_fixed, "w") as f:
                         f.write(self.corrected_pdb)
-                self.information['pdbfixes'] = True
+                self.information["pdbfixes"] = True
 
         if not as_string:
-            self.sourcefiles['filename'] = os.path.basename(self.sourcefiles['pdbcomplex'])
+            self.sourcefiles["filename"] = os.path.basename(
+                self.sourcefiles["pdbcomplex"]
+            )
         self.protcomplex, self.filetype = read_pdb(self.corrected_pdb, as_string=True)
 
         # Update the model in the Mapper class instance
         self.Mapper.original_structure = self.protcomplex.OBMol
-        logger.info('PDB structure successfully read')
+        logger.info("PDB structure successfully read")
 
         # Determine (temporary) PyMOL Name from Filename
-        self.pymol_name = pdbpath.split('/')[-1].split('.')[0] + '-Protein'
+        self.pymol_name = pdbpath.split("/")[-1].split(".")[0] + "-Protein"
         # Replace characters causing problems in PyMOL
-        self.pymol_name = self.pymol_name.replace(' ', '').replace('(', '').replace(')', '').replace('-', '_')
+        self.pymol_name = (
+            self.pymol_name.replace(" ", "")
+            .replace("(", "")
+            .replace(")", "")
+            .replace("-", "_")
+        )
         # But if possible, name it after PDBID in Header
-        if 'HEADER' in self.protcomplex.data:  # If the PDB file has a proper header
-            potential_name = self.protcomplex.data['HEADER'][56:60].lower()
-            if extract_pdbid(potential_name) != 'UnknownProtein':
+        if "HEADER" in self.protcomplex.data:  # If the PDB file has a proper header
+            potential_name = self.protcomplex.data["HEADER"][56:60].lower()
+            if extract_pdbid(potential_name) != "UnknownProtein":
                 self.pymol_name = potential_name
-        logger.debug(f'PyMOL name set as: {self.pymol_name}')
+        logger.debug(f"PyMOL name set as: {self.pymol_name}")
 
         # Extract and prepare ligands
-        ligandfinder = LigandFinder(self.protcomplex, self.altconf, self.modres, self.covalent, self.Mapper)
+        ligandfinder = LigandFinder(
+            self.protcomplex, self.altconf, self.modres, self.covalent, self.Mapper
+        )
         self.ligands = ligandfinder.ligands
         self.excluded = ligandfinder.excluded
 
         # decide whether to add polar hydrogens
         if not config.NOHYDRO:
             if not as_string:
-                basename = os.path.basename(pdbpath).split('.')[0]
+                basename = os.path.basename(pdbpath).split(".")[0]
             else:
                 basename = "from_stdin"
             self.protcomplex.OBMol.AddPolarHydrogens()
-            output_path = os.path.join(self._output_path, f'{basename}_protonated.pdb')
-            self.protcomplex.write('pdb', output_path, overwrite=True)
-            logger.info(f'protonated structure written to {output_path}')
+            output_path = os.path.join(self._output_path, f"{basename}_protonated.pdb")
+            self.protcomplex.write("pdb", output_path, overwrite=True)
+            logger.info(f"protonated structure written to {output_path}")
         else:
-            logger.warning('no polar hydrogens will be assigned (make sure your structure contains hydrogens)')
+            logger.warning(
+                "no polar hydrogens will be assigned (make sure your structure contains hydrogens)"
+            )
 
         for atm in self.protcomplex:
             self.atoms[atm.idx] = atm
 
         if len(self.excluded) != 0:
-            logger.info(f'excluded molecules as ligands: {self.excluded}')
+            logger.info(f"excluded molecules as ligands: {self.excluded}")
 
         if config.DNARECEPTOR:
-            self.resis = [obres for obres in pybel.ob.OBResidueIter(
-                self.protcomplex.OBMol) if obres.GetName() in config.DNA + config.RNA]
+            self.resis = [
+                obres
+                for obres in pybel.ob.OBResidueIter(self.protcomplex.OBMol)
+                if obres.GetName() in config.DNA + config.RNA
+            ]
         else:
-            self.resis = [obres for obres in pybel.ob.OBResidueIter(
-                self.protcomplex.OBMol) if obres.GetResidueProperty(0)]
+            self.resis = [
+                obres
+                for obres in pybel.ob.OBResidueIter(self.protcomplex.OBMol)
+                if obres.GetResidueProperty(0)
+            ]
 
         num_ligs = len(self.ligands)
         if num_ligs == 1:
-            logger.info('analyzing one ligand')
+            logger.info("analyzing one ligand")
         elif num_ligs > 1:
-            logger.info(f'analyzing {num_ligs} ligands')
+            logger.info(f"analyzing {num_ligs} ligands")
         else:
-            logger.info(f'structure contains no ligands')
+            logger.info(f"structure contains no ligands")
 
     def analyze(self):
         """Triggers analysis of all complexes in structure"""
@@ -1406,42 +2203,66 @@ class PDBComplex:
 
         single_sites = []
         for member in ligand.members:
-            single_sites.append(':'.join([str(x) for x in member]))
-        site = ' + '.join(single_sites)
-        site = site if not len(site) > 20 else site[:20] + '...'
-        longname = ligand.longname if not len(ligand.longname) > 20 else ligand.longname[:20] + '...'
-        ligtype = 'unspecified type' if ligand.type == 'UNSPECIFIED' else ligand.type
-        ligtext = f'{longname} [{ligtype}] -- {site}'
-        logger.info(f'processing ligand {ligtext}')
-        if ligtype == 'PEPTIDE':
-            logger.info(f'chain {ligand.chain} will be processed in [PEPTIDE / INTER-CHAIN] mode')
-        if ligtype == 'INTRA':
-            logger.info(f'chain {ligand.chain} will be processed in [INTRA-CHAIN] mode')
-        any_in_biolip = len(set([x[0] for x in ligand.members]).intersection(config.biolip_list)) != 0
-
-        if ligtype not in ['POLYMER', 'DNA', 'ION', 'DNA+ION', 'RNA+ION', 'SMALLMOLECULE+ION'] and any_in_biolip:
-            logger.info('may be biologically irrelevant')
+            single_sites.append(":".join([str(x) for x in member]))
+        site = " + ".join(single_sites)
+        site = site if not len(site) > 20 else site[:20] + "..."
+        longname = (
+            ligand.longname
+            if not len(ligand.longname) > 20
+            else ligand.longname[:20] + "..."
+        )
+        ligtype = "unspecified type" if ligand.type == "UNSPECIFIED" else ligand.type
+        ligtext = f"{longname} [{ligtype}] -- {site}"
+        logger.info(f"processing ligand {ligtext}")
+        if ligtype == "PEPTIDE":
+            logger.info(
+                f"chain {ligand.chain} will be processed in [PEPTIDE / INTER-CHAIN] mode"
+            )
+        if ligtype == "INTRA":
+            logger.info(f"chain {ligand.chain} will be processed in [INTRA-CHAIN] mode")
+        any_in_biolip = (
+            len(set([x[0] for x in ligand.members]).intersection(config.biolip_list))
+            != 0
+        )
+
+        if (
+            ligtype
+            not in ["POLYMER", "DNA", "ION", "DNA+ION", "RNA+ION", "SMALLMOLECULE+ION"]
+            and any_in_biolip
+        ):
+            logger.info("may be biologically irrelevant")
 
         lig_obj = Ligand(self, ligand)
         cutoff = lig_obj.max_dist_to_center + config.BS_DIST
         bs_res = self.extract_bs(cutoff, lig_obj.centroid, self.resis)
         # Get a list of all atoms belonging to the binding site, search by idx
-        bs_atoms = [self.atoms[idx] for idx in [i for i in self.atoms.keys()
-                                                if self.atoms[i].OBAtom.GetResidue().GetIdx() in bs_res]
-                    if idx in self.Mapper.proteinmap and self.Mapper.mapid(idx, mtype='protein') not in self.altconf]
-        if ligand.type == 'PEPTIDE':
+        bs_atoms = [
+            self.atoms[idx]
+            for idx in [
+                i
+                for i in self.atoms.keys()
+                if self.atoms[i].OBAtom.GetResidue().GetIdx() in bs_res
+            ]
+            if idx in self.Mapper.proteinmap
+            and self.Mapper.mapid(idx, mtype="protein") not in self.altconf
+        ]
+        if ligand.type == "PEPTIDE":
             # If peptide, don't consider the peptide chain as part of the protein binding site
-            bs_atoms = [a for a in bs_atoms if a.OBAtom.GetResidue().GetChain() != lig_obj.chain]
-        if ligand.type == 'INTRA':
+            bs_atoms = [
+                a for a in bs_atoms if a.OBAtom.GetResidue().GetChain() != lig_obj.chain
+            ]
+        if ligand.type == "INTRA":
             # Interactions within the chain
-            bs_atoms = [a for a in bs_atoms if a.OBAtom.GetResidue().GetChain() == lig_obj.chain]
+            bs_atoms = [
+                a for a in bs_atoms if a.OBAtom.GetResidue().GetChain() == lig_obj.chain
+            ]
         bs_atoms_refined = []
 
         # Create hash with BSRES -> (MINDIST_TO_LIG, AA_TYPE)
         # and refine binding site atom selection with exact threshold
         min_dist = {}
         for r in bs_atoms:
-            bs_res_id = ''.join([str(whichresnumber(r)), whichchain(r)])
+            bs_res_id = "".join([str(whichresnumber(r)), whichchain(r)])
             for l in ligand.mol.atoms:
                 distance = euclidean3d(r.coords, l.coords)
                 if bs_res_id not in min_dist:
@@ -1451,25 +2272,40 @@ class PDBComplex:
                 if distance <= config.BS_DIST and r not in bs_atoms_refined:
                     bs_atoms_refined.append(r)
         num_bs_atoms = len(bs_atoms_refined)
-        logger.info(f'binding site atoms in vicinity ({config.BS_DIST} A max. dist: {num_bs_atoms})')
-
-        bs_obj = BindingSite(bs_atoms_refined, self.protcomplex, self, self.altconf, min_dist, self.Mapper)
+        logger.info(
+            f"binding site atoms in vicinity ({config.BS_DIST} A max. dist: {num_bs_atoms})"
+        )
+
+        bs_obj = BindingSite(
+            bs_atoms_refined,
+            self.protcomplex,
+            self,
+            self.altconf,
+            min_dist,
+            self.Mapper,
+        )
         pli_obj = PLInteraction(lig_obj, bs_obj, self)
         self.interaction_sets[ligand.mol.title] = pli_obj
 
     def extract_bs(self, cutoff, ligcentroid, resis):
         """Return list of ids from residues belonging to the binding site"""
-        return [obres.GetIdx() for obres in resis if self.res_belongs_to_bs(obres, cutoff, ligcentroid)]
+        return [
+            obres.GetIdx()
+            for obres in resis
+            if self.res_belongs_to_bs(obres, cutoff, ligcentroid)
+        ]
 
     def res_belongs_to_bs(self, res, cutoff, ligcentroid):
         """Check for each residue if its centroid is within a certain distance to the ligand centroid.
         Additionally checks if a residue belongs to a chain restricted by the user (e.g. by defining a peptide chain)"""
-        rescentroid = centroid([(atm.x(), atm.y(), atm.z()) for atm in pybel.ob.OBResidueAtomIter(res)])
+        rescentroid = centroid(
+            [(atm.x(), atm.y(), atm.z()) for atm in pybel.ob.OBResidueAtomIter(res)]
+        )
         # Check geometry
         near_enough = True if euclidean3d(rescentroid, ligcentroid) < cutoff else False
         # Check chain membership
         restricted_chain = True if res.GetChain() in config.PEPTIDES else False
-        return (near_enough and not restricted_chain)
+        return near_enough and not restricted_chain
 
     def get_atom(self, idx):
         return self.atoms[idx]