private function getRegion($time_zone)
    {
        $region = null;

        if ($time_zone === 'UTC') {
            $region = 'Coordinated_Universal_Time'; // fake region for UTC
        } elseif ($time_zone !== null) {
            $parts = explode('/', $time_zone, 2);
            $region = end($parts);
        }

        return $region;
    }