src/Zenaton/v1/Traits/WithDuration.php
public static function timezone($timezone)
    {
        if (!in_array($timezone, DateTimeZone::listIdentifiers())) {
            throw new ExternalZenatonException('Unknown timezone');
        }

        self::$_timezone = $timezone;
    }
public static function timezone($timezone)
    {
        if (!in_array($timezone, DateTimeZone::listIdentifiers())) {
            throw new ExternalZenatonException('Unknown timezone');
        }

        self::$_timezone = $timezone;
    }
Define timezone used when setting date / time.

@param string $timezone A PHP timezone identifier (@see http://php.net/manual/en/timezones.php)