How to send error to payment sheet when users selects shippingaddress with some country where we don't ship?

Hi, I am using paymentrequest api to implement apple pay on the web. In onshippingaddresschange callback i am checking for country of selected shipping address and if its invalid as per our logic i need to show an error using updateWith(). I am not able to figure out structure of object to pass to the function. I tried this one but it didn't work.

event.updateWith({
shippingAddressErrors: {
country : 'invalid country',
addressLine: "Adress  error"
}
})

Can someone help?