public static function create_contact_request_returns() {
        return new external_single_structure(
            array(
                'request' => new external_single_structure(
                    array(
                        'id' => new external_value(PARAM_INT, 'Message id'),
                        'userid' => new external_value(PARAM_INT, 'User from id'),
                        'requesteduserid' => new external_value(PARAM_INT, 'User to id'),
                        'timecreated' => new external_value(PARAM_INT, 'Time created'),
                    ),
                    'request record',
                    VALUE_OPTIONAL
                ),
                'warnings' => new external_warnings()
            )
        );
    }