docs: def _prune_maps_to_sequences(self):
          ''' When we merge the SIFTS maps, we can extend the sequence maps such that they have elements in their domain that we removed
              from the sequence e.g. 1A2P, residue 'B   3 ' is removed because Rosetta barfs on it. Here, we prune the maps so that their
              domains do not have elements that were removed from sequences.'''
  
          for c, seq in self.atom_sequences.iteritems():
              res_ids = [r[0] for r in seq]
              for_removal = []
              for k, _, _ in self.atom_to_seqres_sequence_maps[c]:
                  if k not in res_ids:
                      for_removal.append(k)
              for res_id in for_removal:
                  self.atom_to_seqres_sequence_maps[c].remove(res_id)