# W-INV322

Source: https://xmlvalid.com/rules/W-INV322

> The ValidityPeriod class may only be used when Preordering is the case

- Level: warning
- Rule sets: OIOUBL 2.1 Invoice rules (Denmark) 1.17.2
- Context: `doc:Invoice/cac:InvoiceLine/cac:Price`
- Test: `cac:ValidityPeriod`

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