You can export a notebook as a .py file, or you can save segments of your history into a .py file. But it would be nice to have something a bit more convenient as you're developing code in a notebook, when you find you want to move a couple of functions to a module but keep using them in that notebook.

We also plan to have a simple text file editor so that you can work on a module in the same environment. We're not going to try to build an entire web-based IDE, though.