code: def start(self, channel):
          
  
          if self._started:
              raise InternalError("The method start() was called twice on VirtualIOTileDevice.")
  
          self._push_channel = channel
          self.start_workers()
docs: Start running this virtual device including any necessary worker threads.
  
          Args:
              channel (IOTilePushChannel): the channel with a stream and trace
                  routine for streaming and tracing data through a VirtualInterface