public static function get_status_list() {

        static $list = null;

        if ($list === null) {
            $list = array(
                self::STATUS_IDLE => self::get_status_name(self::STATUS_IDLE),
                self::STATUS_WAITING_FOR_REVIEW => self::get_status_name(self::STATUS_WAITING_FOR_REVIEW),
                self::STATUS_IN_REVIEW => self::get_status_name(self::STATUS_IN_REVIEW));
        }

        return $list;
    }