diff -r 84be86af9161 Lib/packaging/version.py
--- a/Lib/packaging/version.py	Fri Feb 03 02:46:37 2012 +0100
+++ b/Lib/packaging/version.py	Sun Feb 05 15:50:09 2012 +0200
@@ -320,8 +320,7 @@
         NormalizedVersion(rs)
         return rs   # already rational
     except IrrationalVersionError:
-        pass
-    return None
+        return None
 
 
 # A predicate is: "ProjectName (VERSION1, VERSION2, ..)