Trying to install xxx with pip3, for example
ipywidgets 6.0.0 requires widgetsnbextension~=2.0.0, which is not installed.
If you get an error such as
pip3 install --user --upgrade ipywidgets
You are using pip version 10.0.0, however version 19.3.1 is available. You should consider upgrading via the 'pip install --upgrade pip' command.
If it appears in the final sentence of the execution result and disturbs you
pip3 install --user --upgrade pip
Solved with. The error no longer appears.