code: def test_rabit_ops():
      from distributed import Client, LocalCluster
  
      n_workers = 3
      with LocalCluster(n_workers=n_workers) as cluster:
          with Client(cluster) as client:
              run_rabit_ops(client, n_workers)
  
file_path: xgboost/tests/python/test_tracker.py
imports: import re
  import sys
  import numpy
  import pytest
  import xgboost
  from xgboost import RabitTracker, collective
  from xgboost import testing
label_desc: Use image node_id 4 for calling a global function with example usage: test_rabit_ops() without return types