在命令里面执行了下面这个指令升级所有的Python库之后问题来了，先是Kernrl无缘无故不能启动，重启后整个笔记本服务无法运行
Jupyter Notebook报错如下：
Traceback (most recent call last):
File "/usr/bin/jupyter-notebook", line 11, in <module>
load_entry_point('notebook==5.2.2', 'console_scripts', 'jupyter-notebook')()
File "/usr/local/lib/python3.6/dist-packages/pkg_resources/__init__.py", line 484, in load_entry_point
return get_distribution(dist).load_entry_point(group, name)
File "/usr/local/lib/python3.6/dist-packages/pkg_resources/__init__.py", line 2714, in load_entry_point
return ep.load()
File "/usr/local/lib/python3.6/dist-packages/pkg_resources/__init__.py", line 2332, in load
return self.resolve()
File "/usr/local/lib/python3.6/dist-packages/pkg_resources/__init__.py", line 2338, in resolve
module = __import__(self.module_name, fromlist=['__name__'], level=0)
File "/usr/lib/python3/dist-packages/notebook/notebookapp.py", line 43, in <module>
ioloop.install()
File "/usr/lib/python3/dist-packages/zmq/eventloop/ioloop.py", line 210, in install
assert (not ioloop.IOLoop.initialized()) or \
AttributeError: type object 'IOLoop' has no attribute 'initialized'
原因是安装了tornado-5.1.1版本
解决方法为执行安装旧版本的tornado，因为Jupyter还没有支持新版本的tornado
sudo pip install tornado==4.5.3