How to convert an .ICO to .PNG with Python?

I'm trying to convert a batch of .ICO images over to .PNG images in Python. I have quite a few images to go through so I'd like to find a programmatic solution. I've tried using PIL but I can't seem to get the images and transparency to come out correctly.

I'd prefer to use Python but if it can't be done a开发者_StackOverflownother language or library would also help.

See http://code.google.com/p/casadebender/wiki/Win32IconImagePlugin

It's a PIL plugin that makes it handle Windows icons properly.

If it's just a batch job, why not just use imagemagick?