code: def sensor_id(self):
          
          if hasattr(self, '_sensor_id'):
              return self._sensor_id
          relationships = self._json_data.get('relationships')
          sensor_id = relationships.get('sensor').get('data').get('id')
          self._sensor_id = sensor_id
          return sensor_id
docs: The id of the sensor of this data point.
  
          Returns:
  
              The id of the sensor that generated this datapoint. Will
              throw an AttributeError if no sensor id was found in the
              underlyign data.