{'type': 'boolean'}

def _validate_empty(self, empty, field, value):
        """ {'type': 'boolean'} """
        if isinstance(value, Iterable) and len(value) == 0:
            self._drop_remaining_rules(
                'allowed', 'forbidden', 'items', 'minlength', 'maxlength',
                'regex', 'validator')
            if not empty:
                self._error(field, errors.EMPTY_NOT_ALLOWED)