code: def toggle(self, *args):
          
          self._stop_blink()
          if args:
              for index in args:
                  self[index].toggle()
          else:
              super(LEDBoard, self).toggle()
docs: If no arguments are specified, toggle the state of all LEDs. If
          arguments are specified, they must be the indexes of the LEDs you wish
          to toggle. For example::
  
              from gpiozero import LEDBoard
  
              leds = LEDBoard(2, 3, 4, 5)
              leds.toggle(0)   # turn on the first LED (pin 2)
              leds.toggle(-1)  # turn on the last LED (pin 5)
              leds.toggle()    # turn the first and last LED off, and the
                               # middle pair on
  
          If :meth:`blink` is currently active, it will be stopped first.
  
          :param int args:
              The index(es) of the LED(s) to toggle. If no indexes are specified
              toggle the state of all LEDs.