If the group "DIRECT DEBIT" (BG-19) is delivered, the element "Bank assigned creditor identifier" (BT-90) shall be provided.
(/ubl-invoice:Invoice | /ubl-creditnote:CreditNote)[$supplierCountryIsDE and $customerCountryIsDE]not(cac:PaymentMeans/cac:PaymentMandate)                        or (cac:AccountingSupplierParty/cac:Party/cac:PartyIdentification/cbc:ID[@schemeID='SEPA']                          | cac:PayeeParty/cac:PartyIdentification/cbc:ID[@schemeID='SEPA'])