Message

Attribute 'listID' MUST contain value 'ISO3166-1:Alpha2'

Context
/ubl:Invoice/cac:InvoiceLine/cac:Item/cac:OriginCountry/cbc:IdentificationCode
Test
not(@listID) or @listID = 'ISO3166-1:Alpha2'
Usage
/ ubl:Invoice / cac:InvoiceLine / cac:Item / cac:OriginCountry / cbc:IdentificationCode / @listID