AttributeError: 'NoneType' object has no attribute 'event_broker'

I am trying to run my bot in the commandline. and getting this error

  def run(dbug=False):
        if dbug:
            init_debug_logging()
        interpreter = RasaNLUInterpreter('./model_save/test3/nlu')
        action_endpoint = EndpointConfig(url="http://localhost:5056/webhook")
        agent = Agent.load("model_save/test3", interpreter=interpreter,action_endpoint=action_endpoint)
        rasa.core.run.serve_application(agent,channel='cmdline')
        
    run()

error log:

C:\Users\Raihan\Anaconda3\envs\tf_gpu\lib\site-packages\rasa\core\policies\keras_policy.py:265: FutureWarning: 'KerasPolicy' is deprecated and will be removed in version 2.0. Use 'TEDPolicy' instead.
  current_epoch=meta["epochs"],
[2020-04-14 09:42:36 +0600] [4312] [ERROR] Experienced exception while trying to serve
Traceback (most recent call last):
  File "C:\Users\Raihan\Anaconda3\envs\tf_gpu\lib\site-packages\sanic\app.py", line 1172, in run
    serve(**server_settings)
  File "C:\Users\Raihan\Anaconda3\envs\tf_gpu\lib\site-packages\sanic\server.py", line 918, in serve
    trigger_events(before_start, loop)
  File "C:\Users\Raihan\Anaconda3\envs\tf_gpu\lib\site-packages\sanic\server.py", line 674, in trigger_events
    loop.run_until_complete(result)
  File "C:\Users\Raihan\Anaconda3\envs\tf_gpu\lib\asyncio\base_events.py", line 587, in run_until_complete
    return future.result()
  File "C:\Users\Raihan\Anaconda3\envs\tf_gpu\lib\site-packages\rasa\core\run.py", line 239, in load_agent_on_start
    _broker = EventBroker.create(endpoints.event_broker)
AttributeError: 'NoneType' object has no attribute 'event_broker'
Traceback (most recent call last):

  File "<ipython-input-9-860568e93394>", line 9, in <module>
    run()

  File "<ipython-input-9-860568e93394>", line 7, in run
    rasa.core.run.serve_application(agent,channel='cmdline')

  File "C:\Users\Raihan\Anaconda3\envs\tf_gpu\lib\site-packages\rasa\core\run.py", line 212, in serve_application
    endpoints.lock_store if endpoints else None

  File "C:\Users\Raihan\Anaconda3\envs\tf_gpu\lib\site-packages\sanic\app.py", line 1172, in run
    serve(**server_settings)

  File "C:\Users\Raihan\Anaconda3\envs\tf_gpu\lib\site-packages\sanic\server.py", line 918, in serve
    trigger_events(before_start, loop)

  File "C:\Users\Raihan\Anaconda3\envs\tf_gpu\lib\site-packages\sanic\server.py", line 674, in trigger_events
    loop.run_until_complete(result)

  File "C:\Users\Raihan\Anaconda3\envs\tf_gpu\lib\asyncio\base_events.py", line 587, in run_until_complete
    return future.result()

  File "C:\Users\Raihan\Anaconda3\envs\tf_gpu\lib\site-packages\rasa\core\run.py", line 239, in load_agent_on_start
    _broker = EventBroker.create(endpoints.event_broker)

AttributeError: 'NoneType' object has no attribute 'event_broker'

Drop the url=. Here’s a workbook example

thanks