public static function get_scorm_sco_tracks_returns() {

        return new external_single_structure(
            array(
                'data' => new external_single_structure(
                    array(
                        'attempt' => new external_value(PARAM_INT, 'Attempt number'),
                        'tracks' => new external_multiple_structure(
                            new external_single_structure(
                                array(
                                    'element' => new external_value(PARAM_RAW, 'Element name'),
                                    'value' => new external_value(PARAM_RAW, 'Element value')
                                ), 'Tracks data'
                            )
                        ),
                    ), 'SCO data'
                ),
                'warnings' => new external_warnings(),
            )
        );
    }