diff --git a/Lib/functools.py b/Lib/functools.py
index 71022e5..36466f9 100644
--- a/Lib/functools.py
+++ b/Lib/functools.py
@@ -16,7 +16,10 @@
 try:
     from _thread import RLock
 except:
-    from dummy_threading import RLock
+    class RLock:
+        'Dummy reentrant lock'
+        def __enter__(self): pass
+        def __exit__(self, exctype, excinst, exctb): pass
 
 
 ################################################################################