code: def dump_next(self):
          
  
          if self.dump_walker is None:
              return pack_error(ControllerSubsystem.SENSOR_LOG, SensorLogError.STREAM_WALKER_NOT_INITIALIZED)
  
          try:
              return self.dump_walker.pop()
          except StreamEmptyError:
              return None
docs: Dump the next reading from the stream.
  
          Returns:
              IOTileReading: The next reading or None if there isn't one