Value MUST be part of code list 'Country codes (ISO 3166-1:Alpha2)'.
/ubl:DespatchAdvice/cac:Shipment/cac:Delivery/cac:Despatch/cac:DespatchAddress/cac:Country/cbc:IdentificationCode
(some $code in $clISO3166 satisfies $code = normalize-space(text()))