Ask HN: Is there a Python text editor with live updating?

I've been using the Calca app for a week now, and I really like the fact that you can type out your calculations, evaluate them in the text editor itself, go back and change variables and functions and they will be updated automatically. See how it works here: http://calca.io/

However, there are things i'd like to do that would be much easier to do in Python. Does anyone know of a Calca-like Python text editor?