Message

Value MUST be part of code list 'ISO 3166-1:Alpha2 Country codes'.

Context
/ubl:Catalogue/cac:ProviderParty/cac:PostalAddress/cac:Country/cbc:IdentificationCode
Test
(some $code in $clISO3166 satisfies $code = normalize-space(text()))
Code lists
ISO 3166-1:Alpha2 Country codes
Usage
/ ubl:Catalogue / cac:ProviderParty / cac:PostalAddress / cac:Country / cbc:IdentificationCode