Anaconda中启动jupyter notebook 发生AttributeError: type object ‘IOLoop‘ has no attribute ‘initialized‘

完整错误信息

Traceback (most recent call last):
File “C:\ProgramData\anaconda3\envs\csdn_dl\Scripts\jupyter-notebook-script.py”, line 3, in
import notebook.notebookapp
File “C:\ProgramData\anaconda3\envs\csdn_dl\lib\site-packages\notebook\notebookapp.py”, line 33, in
ioloop.install()
File “C:\ProgramData\anaconda3\envs\csdn_dl\lib\site-packages\zmq\eventloop\ioloop.py”, line 210, in install
assert (not ioloop.IOLoop.initialized()) or
AttributeError: type object ‘IOLoop’ has no attribute ‘initialized’

查看到原先的tornado版本为6.1，可能太高了，选择降低版本

pip list

我的解决方案

pip uninstall tornado
pip install tornado==4.5.3

然后继续启动notebook又产生了另外一个错误
ImportError: cannot import name ‘secure_write’
解决办法

pip install --upgrade jupyter_client

顺利解决~~