[w8rbt]

This is my biggest issue with Python. I absolutely love the language, but Python 3 ought to be Python 3 no matter where/how you got it. If you are using 3.5 and I'm using 3.7 we ought to be able to share code and things just work. Unfortunately, that is not the case.

[jnwatson]

Why would that not work?

[torte]

There are some breaking features from added in 3.7 which were not in the language in 3.7. Meaning code written for the newer Python 3 version might not work with the older Python 3 version. Most of those additions are relatively easy to fix though.

Code from an older Python 3 version should always work in the newer Python 3 version though (at least for 3.5 -> 3.7).

[mdtusz]

You'd think, but it's not always the case. I've recently encountered an issue with eventlet that is only present in 3.7, for example.

[snorkasaurus]

I agree. Try pyenv. It lets you install a particular version for use in a shell account, then `python -m venv venv`. I like pip-tools for requirements management, but some reasonable people disagree.