code: def tag_torsion_angles(self, force=False):
          
          for polymer in self._molecules:
              if polymer.molecule_type == 'protein':
                  polymer.tag_torsion_angles(force=force)
          return
docs: Tags each `Monomer` in the `Assembly` with its torsion angles.
  
          Parameters
          ----------
          force : bool, optional
              If `True`, the tag will be run even if `Monomers` are already
              tagged.