Message

A tender clarification request Identifier MUST be expressed in a UUID syntax (RFC 4122)

Context
ubl:Enquiry/cbc:ID
Test
matches(normalize-space(.),'^[a-fA-F0-9]{8}(\-[a-fA-F0-9]{4}){3}\-[a-fA-F0-9]{12}$')
Usage
/ t009:Enquiry / cbc:ID