{'oneof': [
                {'type': 'callable'},
                {'type': 'list',
                 'schema': {'oneof': [{'type': 'callable'},
                                      {'type': 'string'}]}},
                {'type': 'string'}
                ]}

def _validate_validator(self, validator, field, value):
        """ {'oneof': [
                {'type': 'callable'},
                {'type': 'list',
                 'schema': {'oneof': [{'type': 'callable'},
                                      {'type': 'string'}]}},
                {'type': 'string'}
                ]} """
        if isinstance(validator, _str_type):
            validator = self.__get_rule_handler('validator', validator)
            validator(field, value)
        elif isinstance(validator, Iterable):
            for v in validator:
                self._validate_validator(v, field, value)
        else:
            validator(field, value, self._error)