Add swappable CSS for HTML previews.

[librarian.git] / librarian / parser.py

diff --git a/librarian/parser.py b/librarian/parser.py
index 73ddd52..efe6e95 100644 (file)
--- a/librarian/parser.py
+++ b/librarian/parser.py
@@ -39,7 +39,7 @@ class WLDocument(object):
             self.rdf_elem = root_elem.find(dc_path)
 
             if self.rdf_elem is None:
-                raise NoDublinCore('Document has no DublinCore - which is required.')
+                raise NoDublinCore("Document must have a '%s' element." % RDFNS('RDF'))
 
             self.book_info = dcparser.BookInfo.from_element(
                     self.rdf_elem, fallbacks=meta_fallbacks, strict=strict)