docs: def export_sensor(self, sensor):
          """Return (value, unit) from a sensor node."""
          value = None
          unit = None
          try:
              container = self.sensor_data.get(sensor)
              unit = container.get('unit')
              data_point = container.get('data', [[0, [0.0]]])
              if data_point and data_point[0]:
                  value = data_point[0][-1][0]
          except (ValueError, KeyError, AttributeError):
              pass
  
          return (value, unit)