SF patch 1631942 by Collin Winter:

(a) "except E, V" -> "except E as V"
(b) V is now limited to a simple name (local variable)
(c) V is now deleted at the end of the except block

Lib/test/test_traceback.py

@@ -12,7 +12,7 @@ class TracebackCases(unittest.TestCase):
     def get_exception_format(self, func, exc):
         try:
             func()
-        except exc, value:
+        except exc as value:
             return traceback.format_exception_only(exc, value)
         else:
             raise ValueError, "call did not raise exception"