Message

Value MUST be part of code list 'Electronic Address Scheme (EAS)'.

Context
/ubl:DespatchAdvice/cac:DespatchSupplierParty/cac:Party/cbc:EndpointID
Test
not(@schemeID) or (some $code in $cleas satisfies $code = @schemeID)
Code lists
Electronic Address Scheme (EAS)
Usage
/ ubl:DespatchAdvice / cac:DespatchSupplierParty / cac:Party / cbc:EndpointID / @schemeID