public static function fetch_subscription_cache($forumid, $userid) {
        if (isset(self::$forumcache[$userid]) && isset(self::$forumcache[$userid][$forumid])) {
            return self::$forumcache[$userid][$forumid];
        }
        self::fill_subscription_cache($forumid, $userid);

        if (!isset(self::$forumcache[$userid]) || !isset(self::$forumcache[$userid][$forumid])) {
            return false;
        }

        return self::$forumcache[$userid][$forumid];
    }