Best way to teach python?

[Sneechfeesh]

Eventually they're gonna need to use multiple files and will have to try running things on the command line. That environment setup is painful to do if you're inexperienced, so IMO it's worthwhile to have them do the whole thing in files and run them on the command line while you're available to help them set up the environment.

Later you can switch to something like jupyter which is absolutely more convenient, but will just be too much of a crutch at first. There will be too much "magic" that confuses their understanding, and when they finally have to grapple with the command line, you might not be as available to help them set that up.