Message

Attachment/ExternalReference SHOULD NOT contain any elements but DocumentHash, HashAlgorithmMethod, MimeCode, FileName

Context
ubl:Tender/cac:DocumentReference/cac:Attachment/cac:ExternalReference
Test
count(./*)-count(./cbc:DocumentHash)-count(./cbc:HashAlgorithmMethod)-count(./cbc:MimeCode)-count(./cbc:FileName)=0