docs: def add(self, sensor):
          """Add a sensor, warning if it exists."""
          if isinstance(sensor, (list, tuple)):
              for sss in sensor:
                  self.add(sss)
              return
  
          if not isinstance(sensor, Sensor):
              raise TypeError("pysma.Sensor expected")
  
          if sensor.name in self:
              old = self[sensor.name]
              self.__s.remove(old)
              _LOGGER.warning("Replacing sensor %s with %s", old, sensor)
  
          if sensor.key in self:
              _LOGGER.warning("Duplicate SMA sensor key %s", sensor.key)
  
          self.__s.append(sensor)