public static function getTimezoneLabel($tz_id, $format = false, $ts = 'now') {
		if (self::isValidTimezone($tz_id) && $format) {
			$dt = new DateTime(null, new DateTimeZone($tz_id));
			(is_int($ts)) ? $dt->setTimestamp($ts) : $dt->modify($ts);
			return $dt->format($format);
		}

		return elgg_echo($tz_id);
	}