diff --git a/koji/__init__.py b/koji/__init__.py
index 4d0e7b25..11f6cba4 100644
--- a/koji/__init__.py
+++ b/koji/__init__.py
@@ -3445,7 +3445,7 @@ class ClientSession(object):
 
     def exclusiveSession(self, force=False):
         """Make this session exclusive"""
-        self._callMethod('exclusiveSession', {'force': force})
+        self._callMethod('exclusiveSession', (), {'force': force})
         self.exclusive = True