@dbader Hey Dane, can you check this PR opened a long time ago?

Hey, Mario. Thanks for submitting your PR! And sorry for taking so long to respond.

Aliasing isn't perfect because it conflicts with virtual environments. If you define an alias, it'll silently take precedence over an active environment:

$ python -m venv env
$ . env/bin/activate
(env) $ which python
/home/jdoe/project/env/bin/python
(env) $ python --version
Python 3.8.0
(env) $ alias python=/usr/bin/python2.7
(env) $ python --version
Python 2.7.17
(env) $ which python
/home/jdoe/project/env/bin/python  # <- Python 3.8
(env) $ $(which python) --version
Python 3.8.0

If that's not confusing enough, other commands would also require aliasing. Setting an alias just for the python command won't change the pip one, for example:

(env) $ alias python=/usr/bin/python2.7
(env) $ python --version
Python 2.7.17
(env) $ pip --version
pip 19.2.3 from /home/jdoe/project/env/lib/python3.8/site-packages/pip (python 3.8)

A safer bet would be to stick to the virtual environments or use pyenv to manage the installed Python versions.