public function offset($timezone)
    {
        $timeOffset = (new \DateTimeZone($timezone))->getOffset(new \DateTime('now', new \DateTimeZone('UTC')));

        if($timeOffset < 0) {

            return 'UTC -'. gmdate('H:i', -$timeOffset);

        } else {

            return 'UTC +'. gmdate('H:i', $timeOffset);
        }
    }