# PEPPOL-T01-B28501

Source: https://xmlvalid.com/rules/PEPPOL-T01-B28501

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

- Level: error
- Rule sets: Peppol Order rules 3.7
- Context: `/ubl:Order/cac:OrderLine/cac:LineItem/cac:Price/cbc:BaseQuantity`
- Test: `not(@unitCode) or (some $code in $clUNECERec20 satisfies $code = @unitCode)`

Validate a document against these rules: https://xmlvalid.com/validate