Value MUST be part of code list 'ISO 3166-1:Alpha2 Country codes'.
/ubl:TendererQualification/cac:TendererPartyQualification/cac:MainQualifyingParty/cac:Party/cac:PostalAddress/cac:Country/cbc:IdentificationCode(some $code in $clISO3166 satisfies $code = normalize-space(text()))