I think I'm missing something basic:  I'd like to have something like this:

#+begin_src python

#+filename: foo.py

Instead of storing my Python code in the current org file, I would like

Babel to read foo.py and execute it, as if it was inside the .org file.

The foo.py mentioned above is fairly large, and I would like the code

to be stored in a different file than my .org file, for brevity.

Any ideas?  I feel like I'm missing something obvious.

Thanks,

--Nate