def toggle_buttons(self):
        """Turn buttons on and off."""
        all_time_on = self.all_time.get_value()
        all_chan_on = self.all_chan.get_value()

        self.times['beg'].setEnabled(not all_time_on)
        self.times['end'].setEnabled(not all_time_on)
        self.idx_chan.setEnabled(not all_chan_on)
Turn buttons on and off.