# F-LIB006

Source: https://xmlvalid.com/rules/F-LIB006

> Invalid …. Must be of this form '6E09886B-DC6E-439F-82D1-7CCAC7F4E3B1'

- Level: error
- Rule sets: OIOUBL 2.1 Invoice rules (Denmark) 1.17.2, OIOUBL 2.1 Credit Note rules (Denmark) 1.17.2, OIOUBL 2.1 Reminder rules (Denmark) 1.17.2
- Test: `string-length(string(.)) = 36`

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