public function voidOrRefundInvoice($number, $id = null)
    {
        return new CheddarGetter_Response(
                                                                $this->request(
                                                                    '/invoices/void-or-refund/' . (($id) ? 'id/'.$id : 'number/'.$number),
                                                                    array('bogus' => 'make this a post')
                                                                    )
                                                                );
    }