Message

Value MUST be part of code list 'Document Reference Content Types'.

Context
/espd-req:ESPDRequest/cac:AdditionalDocumentReference/cbc:DocumentTypeCode
Test
(some $code in $clDocRefContentType satisfies $code = normalize-space(text()))
Code lists
Document Reference Content Types
Usage
/ espd-req:ESPDRequest / cac:AdditionalDocumentReference / cbc:DocumentTypeCode