(PHP 5.1.6)致命错误:找不到类'DateTimeZone'

How can i run this code on PHP 5.1.6

$tz = new DateTimeZone($obj['timezone']);

without upgrading my PHP version?

or is there any alternative?

I'am getting this error

PHP Fatal error: Class 'DateTimeZone' not found

Thank you

PHP 5.1.x has only experimental support for DateTime

http://php.net/manual/en/datetime.installation.php

Note: Experimental DateTime support in PHP 5.1.x

Although the DateTime class (and related functions) are enabled by default since PHP 5.2.0, it is possible to add experimental support into PHP 5.1.x by using the following flag before configure/compile: CFLAGS=-DEXPERIMENTAL_DATE_SUPPORT=1

date_default_timezone_set('America/Los_Angeles'); //set your timezone

$tz = date_default_timezone_get(); //display timezone

$date = date('Y:m:d'); //display date