Fix __repr__ of hyperdb.Class

If a error occurs during schema parsing, classname isn't known
yet, account for this case in __repr__.

Author: schlatterbeck

roundup/hyperdb.py

@@ -1076,8 +1076,12 @@ def __init__(self, db, classname, **properties):
 
     def __repr__(self):
         """Slightly more useful representation
+           Note that an error message can be raised at a point
+           where self.classname isn't known yet if the error
+           occurs during schema parsing.
         """
-        return '<hyperdb.Class "%s">' % self.classname
+        cn = getattr (self, 'classname', 'Unknown')
+        return '<hyperdb.Class "%s">' % cn
 
     # Editing nodes: