*/
    public static function add($message)
    {
        if (empty(self::$log)) {
            self::$log = new WC_Logger();
            // can't use __get() no a static property unfortunately
        }
        self::$log->add(self::$handle, $message);
    }
    /**
     * Clear entries from the upgrade log.
     */
    public static function clear()
    {
        if (empty(self::$log)) {
            self::$log = new WC_Logger();
        }
        self::$log->clear(self::$handle);
    }
    /**
     * Schedule a hook to automatically clear the log after 8 weeks
     */
    public static function schedule_cleanup()
    {
        $time_to_cleanup = gmdate('U') + self::$weeks_until_cleanup * WEEK_IN_SECONDS;
        self::add(sprintf('Upgrade complete. Scheduling log cleanup for %s GMT/UTC', date('Y-m-d H:i:s', $time_to_cleanup)));
        wc_schedule_single_action($time_to_cleanup, 'woocommerce_subscriptions_clear_upgrade_log');
    }
}
WCS_Upgrade_Logger::init();