code: def _add_task(self, tile_address, coroutine):
          
  
          self.verify_calling_thread(True, "_add_task is not thread safe")
  
          if tile_address not in self._tasks:
              self._tasks[tile_address] = []
  
          task = self._loop.create_task(coroutine)
          self._tasks[tile_address].append(task)
docs: Add a task from within the event loop.
  
          All tasks are associated with a tile so that they can be cleanly
          stopped when that tile is reset.