What on earth are you talking about? If I add `def bar...` to a file foo.py in my PYTHONPATH, it does not suddenly become available in my interactive session, I

What on earth are you talking about? If I add `def bar...` to a file foo.py in my PYTHONPATH, it does not suddenly become available in my interactive session, I need to import it first. Further if I change foo.py even importing it again in the repl (or jupyter notebook) will not have any effect. You will need to use one of several reload hacks which in practice won't work reliably for all sorts of reasons. In contrast, unless my memory severely fails me (and I don't think so, since I just checked against octave), in matlab if you edit a file in the path, it will be auto-imported every time you save it as soon as the repl is non-busy. Have you actually used both matlab and python?