code: def get_corresponding_chains(self, from_pdb_id, from_chain_id, to_pdb_id):
          '''Should be called after get_mutations.'''
          chains = self.chain_map.get(from_pdb_id, {}).get(from_chain_id, {}).get(to_pdb_id, [])
          return sorted(chainsf get_corresponding_chains(self, from_pdb_id, from_chain_id, to_pdb_id):
          '''Should be called after get_mutations.'''
          chains = self.chain_map.get(from_pdb_id, {}).get(from_chain_id, {}).get(to_pdb_id, [])
          return sorted(chains)
docs: Should be called after get_mutations.