diff --git a/Tools/webchecker/wsgui.py b/Tools/webchecker/wsgui.py
index 1bf5f73..c301c6f 100755
--- a/Tools/webchecker/wsgui.py
+++ b/Tools/webchecker/wsgui.py
@@ -22,7 +22,7 @@
 try:
     class Canceled(Exception):
         "Exception used to cancel run()."
-except:
+except (NameError, TypeError):
     Canceled = __name__ + ".Canceled"