docs: def tag_sidechain_dihedrals(self, force=False):
          """Tags each monomer with side-chain dihedral angles
  
          force: bool, optional
              If `True` the tag will be run even if `Residues` are
              already tagged.
          """
          tagged = ['chi_angles' in x.tags.keys() for x in self._monomers]
          if (not all(tagged)) or force:
              for monomer in self._monomers:
                  chi_angles = measure_sidechain_torsion_angles(
                      monomer, verbose=False)
                  monomer.tags['chi_angles'] = chi_angles
          return