diff -r 3b437196c2d8 -r e9a3a22f98b7 server/session.py
--- a/server/session.py	Mon Jul 15 11:45:37 2013 +0200
+++ b/server/session.py	Wed Jun 12 12:28:01 2013 +0200
@@ -227,10 +227,10 @@
         self._record = {}
 
     def __enter__(self):
-        self._condition.__enter__()
+        return self._condition.__enter__()
 
     def __exit__(self, *args):
-        self._condition.__exit__(*args)
+        return self._condition.__exit__(*args)
 
     def record(self, txid, cnxset):
         """Inform the tracker that a txid have acquired a cnxset