Import issue: AttributeError: 'NoneType' object has no attribute 'session'

先从 ipykernel/comm/comm.py 和 matplotlib/backends/backend_nbagg.py 中的 traceback 路径入手，然后从 VS Code 重现 cerebro.plot()。将该执行上下文与 issue 中描述的 Jupyter 相关行为进行比较。Done 应意味着已重现该故障，并且该故障已修复，或已明确记录受支持的执行上下文。

When import the package inside VScode I get an error:

<IPython.core.display.Javascript object>
<IPython.core.display.HTML object>
Traceback (most recent call last):
  File ".\dpseg.py", line 379, in <module>
    run()
  File ".\dpseg.py", line 320, in run
    cerebro.plot()
  File "C:\ProgramData\Anaconda3\lib\site-packages\backtrader\cerebro.py", line 996, in plot
    plotter.show()
  File "C:\ProgramData\Anaconda3\lib\site-packages\backtrader\plot\plot.py", line 817, in show
    self.mpyplot.show()
  File "C:\Users\Mislav\AppData\Roaming\Python\Python38\site-packages\matplotlib\pyplot.py", line 272, in show
    return _show(*args, **kw)
  File "C:\Users\Mislav\AppData\Roaming\Python\Python38\site-packages\matplotlib\backends\backend_nbagg.py", line 261, in show
    manager.show()
  File "C:\Users\Mislav\AppData\Roaming\Python\Python38\site-packages\matplotlib\backends\backend_nbagg.py", line 90, in show
    self._create_comm()
  File "C:\Users\Mislav\AppData\Roaming\Python\Python38\site-packages\matplotlib\backends\backend_nbagg.py", line 122, in _create_comm
    self.add_web_socket(comm)
  File "C:\Users\Mislav\AppData\Roaming\Python\Python38\site-packages\matplotlib\backends\backend_webagg_core.py", line 433, in add_web_socket
    self.resize(w, h)
  File "C:\Users\Mislav\AppData\Roaming\Python\Python38\site-packages\matplotlib\backends\backend_webagg_core.py", line 417, in resize
    self._send_event(
  File "C:\Users\Mislav\AppData\Roaming\Python\Python38\site-packages\matplotlib\backends\backend_webagg_core.py", line 490, in _send_event
    s.send_json(payload)
  File "C:\Users\Mislav\AppData\Roaming\Python\Python38\site-packages\matplotlib\backends\backend_nbagg.py", line 199, in send_json
    self.comm.send({'data': json.dumps(content)})
  File "C:\Users\Mislav\AppData\Roaming\Python\Python38\site-packages\ipykernel\comm\comm.py", line 122, in send
    self._publish_msg('comm_msg',
  File "C:\Users\Mislav\AppData\Roaming\Python\Python38\site-packages\ipykernel\comm\comm.py", line 66, in _publish_msg
    self.kernel.session.send(self.kernel.iopub_socket, msg_type,
AttributeError: 'NoneType' object has no attribute 'session'
Error in atexit._run_exitfuncs:
Traceback (most recent call last):
  File "C:\Users\Mislav\AppData\Roaming\Python\Python38\site-packages\matplotlib\_pylab_helpers.py", line 72, in destroy_all
    manager.destroy()
  File "C:\Users\Mislav\AppData\Roaming\Python\Python38\site-packages\matplotlib\backends\backend_nbagg.py", line 126, in destroy
    self._send_event('close')
  File "C:\Users\Mislav\AppData\Roaming\Python\Python38\site-packages\matplotlib\backends\backend_webagg_core.py", line 490, in _send_event
    s.send_json(payload)
  File "C:\Users\Mislav\AppData\Roaming\Python\Python38\site-packages\matplotlib\backends\backend_nbagg.py", line 199, in send_json
    self.comm.send({'data': json.dumps(content)})
  File "C:\Users\Mislav\AppData\Roaming\Python\Python38\site-packages\ipykernel\comm\comm.py", line 122, in send
    self._publish_msg('comm_msg',
  File "C:\Users\Mislav\AppData\Roaming\Python\Python38\site-packages\ipykernel\comm\comm.py", line 66, in _publish_msg
    self.kernel.session.send(self.kernel.iopub_socket, msg_type,
AttributeError: 'NoneType' object has no attribute 'session'

I have found similar issue few years old, but I don't understand what is the solution to this. It is mentioning jupyter notebook. Do I have to use this package only inside jupyter?