Redirect the set_theme call to also set Tk background color

def set_theme(self, theme_name, toplevel=None, themebg=None):
        """Redirect the set_theme call to also set Tk background color"""
        if self._toplevel is not None and toplevel is None:
            toplevel = self._toplevel
        if self._themebg is not None and themebg is None:
            themebg = self._themebg
        ThemedWidget.set_theme(self, theme_name)
        color = self._get_bg_color()
        if themebg is True:
            self.config(background=color)
        if toplevel is True:
            self._setup_toplevel_hook(color)