fix

src/core/callcenter/ws.py

@@ -67,7 +67,7 @@ class MyNamespace(Namespace):
         emit('login', request.sid)
 
     def on_heartbeat(self, heartbeat):
-        logger.info('heartbeat received: %s', heartbeat)
+        logger.info('heartbeat received: %s %', heartbeat, type(heartbeat))
         pass
 
     def on_OnPrompt(self, event):