Sorry, I'm being too handwave-y, what I meant (and what i assumed parent meant) is simply that those single bytecode operations are safe thanks to the GIL, so y

Sorry, I'm being too handwave-y, what I meant (and what i assumed parent meant) is simply that those single bytecode operations are safe thanks to the GIL, so your dictionary or list isn't going to become corrupted because of simultaneous writes. like l=[], then l.append(1) and l.append(2) running concurrently will not end up in some weird scenario where the length of the list is 1 yet you stored two items... anyways, I agree with the comment you posted higher up in the discussion, and that was my understanding.