The document type code MUST be coded by the invoice and credit note related code lists of UNTDID 1001.
cbc:InvoiceTypeCode | cbc:CreditNoteTypeCode(self::cbc:InvoiceTypeCode and ((not(contains(normalize-space(.), ' ')) and contains(' 80 82 84 380 383 386 393 395 575 623 780 ', concat(' ', normalize-space(.), ' '))))) or (self::cbc:CreditNoteTypeCode and ((not(contains(normalize-space(.), ' ')) and contains(' 81 83 381 396 532 ', concat(' ', normalize-space(.), ' ')))))