Message

Value MUST be part of code list 'Recommendation 20, including Recommendation 21 codes - prefixed with X (UN/ECE)' or 'Recommandation 21 (UN/ECE)'.

Context
/ubl:Invoice/cac:InvoiceLine/cbc:InvoicedQuantity
Test
not(@unitCode) or (some $code in $clUNECERec20 satisfies $code = @unitCode) or (some $code in $clUNECERec21 satisfies $code = @unitCode)
Code lists
Recommendation 20, including Recommendation 21 codes - prefixed with X (UN/ECE), Recommandation 21 (UN/ECE)
Usage
/ ubl:Invoice / cac:InvoiceLine / cbc:InvoicedQuantity / @unitCode