diff --git a/tricircle/tests/unit/network/test_central_plugin.py b/tricircle/tests/unit/network/test_central_plugin.py
index d156d1dc..3674bd30 100644
--- a/tricircle/tests/unit/network/test_central_plugin.py
+++ b/tricircle/tests/unit/network/test_central_plugin.py
@@ -894,6 +894,9 @@ class FakeSession(object):
 
         return dummy_method
 
+    def __contains__(self, item):
+        return False
+
     @property
     def is_active(self):
         return True