code: def registration_options(self):
          
          registration_options = {}
          rs = self.registration_model()
          for k, v in self.__dict__.items():
              if k not in DEFAULT_BASE_FIELDS + ['_state']:
                  try:
                      getattr(rs, k)
                      registration_options.update({k: v})
                  except AttributeError:
                      pass
          registration_identifier = registration_options.get(
              'registration_identifier')
          if registration_identifier:
              registration_options['registration_identifier'] = self.to_string(
                  registration_identifier)
          return registration_options
docs: Gathers values for common attributes between the
          registration model and this instance.