[google-appengine] Debugging with pdb() ?

Call me old school, but I much prefer to do my debugging with pdb, I really don't want to install Eclipse just to debug a small app like this. So, how do I get pdb running under the app engines local server? If I include it as I usualle would (import pdb; pdb.set_trace()) I get a 500 server error

[google-appengine] BadArgumentError: _app must not be empty.

I'm trying to get doctests running from inside of Textmate, and I've got so far that I can run the tests, and they work as expected until I try and put() the object, when I get the error above. I'm using Aral Balkan's gae_doctest.py and I've added os.environ ['APPLICATION_ID'] = APP_ID as suggest