Magento: eliminare un ordine

function deleteOrder($orderId) {
 
    $order = Mage::getModel('sales/order')->load($orderId);
 
    $invoices = $order->getInvoiceCollection();
    foreach ($invoices as $invoice){
        $invoice->delete();
    }
    $creditnotes = $order->getCreditmemosCollection();
    foreach ($creditnotes as $creditnote){
        $creditnote->delete();
    }
    $shipments = $order->getShipmentsCollection();
    foreach ($shipments as $shipment){
        $shipment->delete();
    }
    $order->delete();                
 
    return 0;
}