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/os.py

@@ -163,7 +163,7 @@ def makedirs(name, mode=0777):
     if head and tail and not path.exists(head):
         try:
             makedirs(head, mode)
-        except OSError, e:
+        except OSError as e:
             # be happy if someone already created the path
             if e.errno != EEXIST:
                 raise
@@ -284,7 +284,7 @@ def walk(top, topdown=True, onerror=None):
         # Note that listdir and error are globals in this module due
         # to earlier import-*.
         names = listdir(top)
-    except error, err:
+    except error as err:
         if onerror is not None:
             onerror(err)
         return
@@ -390,7 +390,7 @@ def _execvpe(file, args, env=None):
         fullname = path.join(dir, file)
         try:
             func(fullname, *argrest)
-        except error, e:
+        except error as e:
             tb = sys.exc_info()[2]
             if (e.errno != ENOENT and e.errno != ENOTDIR
                 and saved_exc is None):