When there is a tqdm std bar in existance and Python shuts down, it is possible to hit the following:
In it's __del__ method and in the call to format_dict, you hit this line

because the shutdown causes the import to fail at some point and apparently del is later than that point.

But this returns only None, when it should return two elements, leading to an unable to unpack none exception.
I would suggest to return None, None like in the error case a few lines down.

Of course, my favourite fix would be to not import stuff within a function, but hey, what do I know.