Message

The group "SELLER CONTACT" (BG-6) shall be provided.

Context
(/ubl-invoice:Invoice/cac:AccountingSupplierParty | /ubl-creditnote:CreditNote/cac:AccountingSupplierParty)[$supplierCountryIsDE and $customerCountryIsDE]
Test
cac:Party/cac:Contact
Usage
/ ubl:Invoice / cac:AccountingSupplierParty / cac:Party / cac:Contact
/ ubl:CreditNote / cac:AccountingSupplierParty / cac:Party / cac:Contact