docs: def _validate_return_fields(self, return_fields):
          """
          :param return_fields: tuple
          :raises: pybomb.exceptions.InvalidReturnFieldException
          """
          for return_field in return_fields:
              if return_field not in self.RESPONSE_FIELD_MAP:
                  raise InvalidReturnFieldException(
                      '"{0}" is an invalid return field'.format(return_field)
                  )