{'empty': False }

def _validate_contains(self, expected_values, field, value):
        """ {'empty': False } """
        if not isinstance(value, Iterable):
            return

        if not isinstance(expected_values, Iterable) or isinstance(
            expected_values, _str_type
        ):
            expected_values = set((expected_values,))
        else:
            expected_values = set(expected_values)

        missing_values = expected_values - set(value)
        if missing_values:
            self._error(field, errors.MISSING_MEMBERS, missing_values)