public static function move_field_parameters() {
        return new external_function_parameters(
                ['id' => new external_value(PARAM_INT, 'Id of the field to move', VALUE_REQUIRED),
                 'categoryid' => new external_value(PARAM_INT, 'New parent category id', VALUE_REQUIRED),
                 'beforeid'   => new external_value(PARAM_INT, 'Id of the field before which it needs to be moved',
                     VALUE_DEFAULT, 0)]
        );
    }