code: def distance(self, channel=1):
          
          self._ensure_mode(self.MODE_IR_SEEK)
          channel = self._normalize_channel(channel)
          ret_value = self.value((channel * 2) + 1)
  
          # The value will be -128 if no beacon is found, return None instead
          return None if ret_value == -128 else ret_value
docs: Returns distance (0, 100) to the beacon on the given channel.
          Returns None when beacon is not found.