code: def start(self, callback, rate=SENSOR_DELAY_NORMAL):
          
          if not self.manager:
              raise RuntimeError(
                  "Cannot start a sensor without a SensorManager!")
          self.onSensorChanged.connect(callback)
          return self.manager.registerListener(self.getId(), self, rate)
docs: Start listening to sensor events. Sensor event data depends
          on the type of sensor that was given to 
          
          Parameters
          ----------
              callback: Callable
                  A callback that takes one argument that will be passed
                  the sensor data. Sensor data is a dict with data based on
                  the type of sensor.
              rate: Integer
                  How fast to update. One of the Sensor.SENSOR_DELAY values   
          
          Returns
          -------
              result: Future
                  A future that resolves to whether the register call
                  completed.