Jupyter-notebook not running after Ubuntu upgrade

$ jupyter-notebook 

Traceback (most recent call last):

  File "/usr/local/bin/jupyter-notebook", line 7, in <module>

    from notebook.notebookapp import main

ModuleNotFoundError: No module named 'notebook'

$pip install jupyter --user installed the jupyter-note book.

But I want python3 version.
I tried to install jupyter using following command.

$ pip3 install jupyter --user

Traceback (most recent call last):

  File "/usr/local/bin/pip3", line 7, in <module>

    from pip._internal import main

ModuleNotFoundError: No module named 'pip._internal'

To solve this problem do the following.
Remove the installed jupyter using:

$sudo apt-get uninstall jupyter (and hit 'y' to confirm)

or,

$pip uninstall jupyter

and update using:

$sudo apt-get update

Now do the following:

$sudo apt-get install jupyter-notebook

Now, you can open the jupyter-notebook.

Jupyter Notebook error: AttributeError: type object 'IOLoop' has no attribute 'initialized'

AttributeError: type object 'IOLoop' has no attribute 'initialized'

This error may be due to the tornado==5.0* versions. Using Tornado 4.5.3 solves the problem.

To do this, try

pip3 uninstall tornado

pip3 install tornado==4.5.3

This solved my problem. Comment if this is useful to you.