diff -r b66e82c9f852 Lib/os.py
--- a/Lib/os.py	Tue Jun 26 23:05:27 2012 +0200
+++ b/Lib/os.py	Wed Jun 27 11:01:04 2012 +0300
@@ -388,6 +388,15 @@
             dirs.remove('CVS')  # don't visit CVS directories
     """
 
+    try:
+        fwalk
+    except NameError:
+        pass
+    else:
+        for x in fwalk(top, topdown=topdown, onerror=onerror, followlinks=followlinks):
+            yield x[:-1]
+        return
+
     islink, join, isdir = path.islink, path.join, path.isdir
 
     # We may not have read permission for top, in which case we can't