Cancelling payment throws an error

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I got this error when I inadvertently cancelled the payment at WorldPay:

Notice: Undefined index: cardType in uc_worldpay_complete() (line 236 of sites/all/modules/uc_worldpay/uc_worldpay.module).

I guess that the credit card argument is not returned when the payment is cancelled - there is no card type to return. I am not sure it this will be fixed will a simple:

if (isset($_POST['cardType'])) {
  $card_type = $_POST['cardType'];
}