I also contest the idea that os functions must only be thin shells around system provided calls (even though I don't think that using getrandom instead of reading from /dev/urandom violates that assertion).

There are a number of functions in os.py that add additional logic ontop of the system calls, like:

* os.makedirs
* os.removedirs
* os.renames
* os.walk
* os.popen (which actually imports and uses the entire subprocess module)
* os.scandir

That's just from a quick scan of the pure Python os.py file.