--- urllib3/_collections.py.old	2013-11-26 14:24:31.460633453 +0100
+++ urllib3/_collections.py	2013-11-26 14:25:07.851045715 +0100
@@ -5,7 +5,15 @@
 # the MIT License: http://www.opensource.org/licenses/mit-license.php
 
 from collections import MutableMapping
-from threading import RLock
+try:
+    from threading import RLock
+except ImportError:
+    class RLock:
+        def __enter__(self):
+            pass
+
+        def __exit__(self, exc_type, exc_value, traceback):
+            pass
 
 try: # Python 2.7+
     from collections import OrderedDict