code: def contrast(self, value):
          
          assert(0x00 <= value <= 0xFF)
          self._brightness = value >> 4
          if self._last_image is not None:
              self.display(self._last_image)
docs: Sets the LED intensity to the desired level, in the range 0-255.
  
          :param level: Desired contrast level in the range of 0-255.
          :type level: int