code: @Nullable
    public static Class <?> getImplementationClassOfNamespace (@Nullable final String sNamespace)
    {
      final EUBL21DocumentType eDocType = getDocumentTypeOfNamespace (sNamespace);
      return eDocType == null ? null : eDocType.getImplementationClass ();
    }
docs: Get the domain object class of the passed namespace.
  
  @param sNamespace
  The namespace URI of any UBL 2.1 document type. May be
  <code>null</code>.
  @return <code>null</code> if no such UBL 2.1 document type exists.