Index: trunk/web/webcommon.py
===================================================================
--- trunk/web/webcommon.py	(revision 263)
+++ trunk/web/webcommon.py	(revision 264)
@@ -49,5 +49,5 @@
     def clear(self):
         """Clear the state so future accesses reload it."""
-        for attr in self.__dict__:
+        for attr in list(self.__dict__):
             if attr.startswith('__cache_'):
                 delattr(self, attr)