while working on the patch to add the same feature in rmtree, I realized
this is a non sense since the root folder itself is removed at the end
of the function when all its content is removed.

So, unless we change this behavior, which I doubt it is a good idea, it
won't be possible.

Maybe another API could be added in shutil, in order to do any kind of
treatment in a tree, like removing files, or whatever, and without
copying it like copytree does.