Message

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

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