Since I've been poking around in this area of CPython lately, here's some triviaassociated with frame objects.

First, one might wonder if code executing at the module level literallyhas a CPython frame struct with f_locals being the same as f_globals , or if the C code just leaves f_locals null and fixesthings up behind the scenes when you look from Python code. Theanswer turns out to be that CPython frame structures always havea real f_locals (Python) dictionary

As I noted in passing , Python frame objects alsohave a vaguely mysterious f_builtins member. On one level, frameobjects have this member because they are more or less representationsof the CPython (code) frame structure, and the C-level code framestructure has an f_builtins field. So, what is this field?

(Quite a lot of the Python internal objects work this way; they have themembers that they do mostly because they're Python representations of Cstructures).

We can