AttributeError: module 'pkg_resources' has no attribute 'safe_name' oauthlib install

Found the solution. I had to upgrade setuptools, so:

$ sudo pip3 install --upgrade setuptools

I ran into the same error while running pip inside a virtualenv environment, however setuptools were already up-to-date in my case.

What fixed it for me

# exit the virtualenv
deactivate

# re-initialize your virtual environment (your command may differ)
virtualenv --python=python3.7 env

# activate the virtualenv again
source env/bin/activate

# re-install your dependencies
pip install -r requirements.txt

Root cause

The root cause in my case was that I had accidentally deleted the pkg-resources pip package that virtualenv creates in ubuntu. Since pip install pkg-resouces fails (pkg-resources is not a real pypi package), reinitializing virtualenv is the only way to get that package back.