Index: Lib/idlelib/keybindingDialog.py
===================================================================
--- Lib/idlelib/keybindingDialog.py	(revision 71316)
+++ Lib/idlelib/keybindingDialog.py	(working copy)
@@ -168,7 +168,7 @@
 
     def GetModifiers(self):
         modList = [variable.get() for variable in self.modifier_vars]
-        return filter(None, modList)
+        return [mod for mod in modList if mod]
 
     def ClearKeySeq(self):
         self.listKeysFinal.select_clear(0,END)