code: def test_scatter(obj):
      @gen_cluster(client=True)
      async def run_test(client, scheduler, worker1, worker2):
          obj_fut = await client.scatter(obj)
          fut = client.submit(echo, obj_fut)
          result = await fut
          assert obj.equals(result)
  
      run_test()
  
file_path: distributed/distributed/protocol/tests/test_arrow.py
imports: from __future__ import annotations
  import pytest
  import distributed
  from distributed.protocol import deserialize, serialize, to_serialize
  from distributed.utils_test import gen_cluster
label_desc: Use image node_id 3 for calling a global function with example usage: test_scatter(obj) without return types