bpo-46841: Use inline caching for calls by brandtbucher · Pull Request #31709 · python/cpython

I think the existence of PyList_Type as part of the API means that list.append must be per-process unique.
In other words, list_append could be static.

I'm happy to leave it as is for now, though. We should look to make the whole struct static, although the mutability of builtin functions makes that tricky for isinstance and len.