I had some deja vu recently, cuz of this old thread: https://mail.python.org/pipermail/python-list/2013-May/648245.html
Today the context is different, but the problem remains the same. One of the futurize refactoring tools converts usage of StringIO.StringIO to io.StringIO, which, given that the latter accepts just about anything you through at it, is a bit surprising. Perhaps there is no true corresponding class in the io module? Skip -- https://mail.python.org/mailman/listinfo/python-list