code: def make_pdb(self, alt_states=False, inc_ligands=True):
          
          if any([False if x.id else True for x in self._monomers]):
              self.relabel_monomers()
          if self.ligands and inc_ligands:
              monomers = self._monomers + self.ligands._monomers
          else:
              monomers = self._monomers
          pdb_str = write_pdb(monomers, self.id, alt_states=alt_states)
          return pdb_str
docs: Generates a PDB string for the `Polymer`.
  
          Parameters
          ----------
          alt_states : bool, optional
              Include alternate conformations for `Monomers` in PDB.
          inc_ligands : bool, optional
              Includes `Ligands` in PDB.
  
          Returns
          -------
          pdb_str : str
              String of the pdb for the `Polymer`. Generated using information
              from the component `Monomers`.