public static function getInstance($client = null)
{
if ($client != null) {
$wsdl = 1;
} else {
$wsdl = 0;
}
if (!isset(self::$instance[$wsdl])) {
self::$instance[$wsdl] = new GatewayOrder($client);
}
self::$type_sku = Gateway::getConfig('TYPE_SKU') !== false ? Gateway::getConfig('TYPE_SKU') : 'reference';
return self::$instance[$wsdl];
}