code: def test_max_clients(init_and_serve):
      # Tests max clients. Should support up to CLIENT_SERVER_MAX_THREADS / 2.
      def get_job_id(api):
          return api.get_runtime_context().worker.current_job_id
  
      for i in range(3):
          api1 = _ClientContext()
          info1 = api1.connect("localhost:50051")
  
          assert info1["num_clients"] == i + 1, info1
  
      with pytest.raises(ConnectionError):
          api = _ClientContext()
          _ = api.connect("localhost:50051")
  
imports: import pytest
  import time
  import random
  import sys
  import subprocess
  from unittest.mock import patch
  import ray.util.client.server.server
  import ray.core.generated.ray_client_pb2
  from ray.util.client import _ClientContext, CURRENT_PROTOCOL_VERSION
  from ray.cluster_utils import cluster_not_supported
  import ray
label_desc: Use image node_id 10 for calling a global function with example usage: test_max_clients(init_and_serve) and returns: api