correct callback

app.py

@@ -128,7 +128,7 @@ def stream(input_text) -> Generator:
     # Create a funciton to call - this will run in a thread
 
     def task():
-        resp = agent.run(input_text, callbacks=QueueCallback(q))
+        resp = agent.run(input_text, callbacks=[QueueCallback(q)])
         q.put(job_done)
 
     # Create a thread and start the function