An error is reported when installing supervisor. The information is as follows

web:~# supervisorctl status
/usr/local/lib/python2.7/dist-packages/pkg_resources/py2_warn.py:22: UserWarning: Setuptools will stop working on Python 2
************************************************************
You are running Setuptools on Python 2, which is no longer
supported and
>>> SETUPTOOLS WILL STOP WORKING <<<
in a subsequent release (no sooner than 2020-04-20).
Please ensure you are installing
Setuptools using pip 9.x or later or pin to `setuptools<45`
in your environment.
If you have done those things and are still encountering
this message, please comment in
https://github.com/pypa/setuptools/issues/1458
about the steps that led to this unsupported combination.
************************************************************
  sys.version_info < (3,) and warnings.warn(pre + "*" * 60 + msg + "*" * 60)

Solution:
uninstall and reinstall pip, setuptools and wheel to return them to the version corresponding to the system Python
python3 reference:

python3 -m pip uninstall pip setuptools wheel
sudo apt-get --reinstall install  python3-setuptools python3-wheel python3-pip

Python2 reference:

python -m pip uninstall pip setuptools wheel
sudo apt-get --reinstall install python-setuptools python-wheel python-pip