feature suggestion: extract Python code only

[katrinafyi]

Hello, thanks for the useful project! I'm interested in applying a type-checker to the generator's Python code.

To do this, is there a mode which emits a Python file containing the prologue and every code block in the template file? It does not have to be anything fancy, a simple concatenation will suffice.

I can prepare a patch if you'd like.

[nedbat]

Interesting idea. That doesn't exist yet.