diff --git a/ibm_watson/websocket/synthesize_listener.py b/ibm_watson/websocket/synthesize_listener.py
index dee6e28a..33caf81d 100644
--- a/ibm_watson/websocket/synthesize_listener.py
+++ b/ibm_watson/websocket/synthesize_listener.py
@@ -120,7 +120,7 @@ def on_error(self, ws, error):
         """
         self.callback.on_error(error)
 
-    def on_close(self, ws, **kwargs):
+    def on_close(self, ws, *args, **kwargs):
         """
         Callback executed when websocket connection is closed