def METHOD_NAME():
  params = mmtbx.model.manager.get_default_pdb_interpretation_params()
  params.pdb_interpretation.flip_symmetric_amino_acids=False
  inp_1 = iotbx.pdb.input(lines=tst_model_cart_ref_restraints.pdb_str_h, source_info=None)
  h_model = mmtbx.model.manager(model_input = inp_1)
  h_model.process(pdb_interpretation_params=params, make_restraints=True)
  inp_2 = iotbx.pdb.input(lines=tst_model_cart_ref_restraints.pdb_str, source_info=None)
  model = mmtbx.model.manager(model_input = inp_2)
  model.process(pdb_interpretation_params=params, make_restraints=True)
  params = mmtbx.model.manager.get_default_pdb_interpretation_params()
  params.pdb_interpretation.flip_symmetric_amino_acids=False
  params.reference_model.enabled=True
  params.reference_model.sigma = 2
  # case 1: big model adopting small model.
  h_model.set_reference_torsion_restraints(
      ref_model = model,
      params=params)
  assert h_model.get_restraints_manager().geometry.get_n_reference_dihedral_proxies() == 34
  reference_dihedral_proxies = h_model.get_restraints_manager().geometry.reference_dihedral_manager.reference_dihedral_proxies
  answer = [