test error number

src/rougail/error.py

@@ -29,6 +29,9 @@ class DictConsistencyError(Exception):
     """It's not only that the Creole XML is valid against the Creole DTD
     it's that it is not consistent.
     """
+    def __init__(self, msg, errno):
+        super().__init__(msg)
+        self.errno = errno
 
 
 class LoaderError(Exception):