code: def test_batching_exception(serve_instance):
      @serve.deployment
      class NoListReturned:
          def __init__(self):
              self.count = 0
  
          @serve.batch(max_batch_size=5)
          async def handle_batch(self, requests):
              return len(requests)
  
          async def __call__(self, request):
              return await self.handle_batch(request)
  
      # Set the max batch size.
      handle = serve.run(NoListReturned.bind())
  
      with pytest.raises(ray.exceptions.RayTaskError):
          assert handle.remote(1).result()
  
file_path: ray/python/ray/serve/tests/test_batching.py
imports: import asyncio
  from concurrent.futures.thread import ThreadPoolExecutor
  from functools import partial
  from typing import List
  import pytest
  import requests
  from starlette.responses import StreamingResponse
  import ray
  from ray import serve
label_desc: Use image node_id 2 for calling a global function with example usage: test_batching_exception(serve_instance) and returns: len, unknown