# UBL-SR-44

Source: https://xmlvalid.com/rules/UBL-SR-44

> An Invoice may only have one unique PaymentID, but the PaymentID may be used for multiple PaymentMeans

- Level: error
- Rule sets: EN 16931 rules (UBL) 1.3.17
- Context: `/ubl:Invoice | /cn:CreditNote`
- Test: `count(distinct-values(//cbc:PaymentID)) <= 1`

> An Invoice may only have one unique PaymentID, but the PaymentID may be used for multiple PaymentMeans

- Level: error
- Rule sets: EN 16931 rules 1.3.16 (UBL), EXTENDED-CTC-FR rules (UBL) 1.4.0.04, Romanian RO e-Factura rules (UBL) 1.0.9
- Context: `/ubl:Invoice | /cn:CreditNote`
- Test: `count(//cbc:PaymentID[not(preceding::cbc:PaymentID/. = .)]) <= 1`

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