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
diff --git a/Lib/_strptime.py b/Lib/_strptime.py
index 3fb5602..2d9be36 100644
--- a/Lib/_strptime.py
+++ b/Lib/_strptime.py
@@ -291,7 +291,7 @@
                 format_regex = time_re.compile(format)
             # KeyError raised when a bad format is found; can be specified as
             # \\, in which case it was a stray % but with a space after it
-            except KeyError, err:
+            except KeyError as err:
                 bad_directive = err.args[0]
                 if bad_directive == "\\":
                     bad_directive = "%"