Callbacks registered in the :mod:`tkinter` module now take arguments as various Python objects (int, float, bytes, tuple), not just str. To restore the previous behavior set :mod:`!tkinter` module global :data:`~tkinter.wantobject` to 1 before creating the :class:`~tkinter.Tk` object or call the :meth:`~tkinter.Tk.wantobject` method of the :class:`!Tk` object with argument 1. Calling it with argument 2 restores the current default behavior.