def toggle_single(self, by_label=None):
        """Deprecated: toggle the selection of the single item in this control.
        
        Raises ItemCountError if the control does not contain only one item.
        
        by_label argument is ignored, and included only for backwards
        compatibility.

        """
        deprecation(
            "control.items[0].selected = not control.items[0].selected")
        if len(self.items) != 1:
            raise ItemCountError(
                "'%s' is not a single-item control" + self.name)
        item = self.items[0]
        self._set_selected_state(item, not item.selected)
dataset/ETHPy150Open deanhiller/databus/webapp/play1.3.x/samples-and-tests/i-am-a-developer/mechanize/ClientForm.py/ListControl.toggle_single/operator `%` -> `+`