The Python community tends to look askance at code generation; so, @Hoang, if you think code generation is THE way to go, I suggest you try just about any other language BUT Python.
@Dominic has already suggested some excellent resources, I could point you to more (App Engine Fan, App Engine Utilities, etc, etc) but they're all based on the Pythonic mindset: understand what you need and what you could be doing, wrap as much of it as feasible into reusable components, reuse those components from your own sources.
You want magic, wizards and code generation that basically excused you (in theory) from STUDYING and UNDERSTANDING: give up on Python, it's SO not the language for that,