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_set.py

@@ -332,7 +332,7 @@ class TestSet(TestJointOps):
         for v1 in ['Q', (1,)]:
             try:
                 self.s.remove(v1)
-            except KeyError, e:
+            except KeyError as e:
                 v2 = e.args[0]
                 self.assertEqual(v1, v2)
             else: