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

Tools/scripts/dutree.py

@@ -18,7 +18,7 @@ def main():
         total, d = store(size, comps, total, d)
     try:
         display(total, d)
-    except IOError, e:
+    except IOError as e:
         if e.errno != errno.EPIPE:
             raise