/**
* Main WooCommerce Instance
*
* Ensures only one instance of WooCommerce is loaded or can be loaded.
*
* @since 2.1
* @static
* @see WC()
* @return Main WooCommerce instance
*/
public static function instance()
{
if (is_null(self::$_instance)) {
self::$_instance = new self();
}
return self::$_instance;
}
