code: def get_state(self, channel):
          
          val = None
          if channel not in self._unit:
              return val
          if self._unit[channel] == 'l/h':
              val = ((1000 * 3600) / (self._delay[channel] * self._pulses[channel]))
          elif self._unit[channel] == 'm3/h':
              val = ((1000 * 3600) / (self._delay[channel] * self._pulses[channel]))
          elif self._unit[channel] == 'W':
              val = ((1000 * 1000 * 3600) / (self._delay[channel] * self._pulses[channel]))
              if val < 55:
                  val = 0
          return round(val, 2)
docs: Ignore channel