code: def test_help_exist():
      s = subprocess.check_output(
          ["jina", "help", "port"],
          stderr=subprocess.STDOUT,
      )
      assert "a CLI argument of Jina" in s.decode()
  
imports: import json
  import os
  import subprocess
  import pytest
  from jina.checker import NetworkChecker
  from jina.jaml import JAML
  from jina.orchestrate.pods.factory import PodFactory
  from jina.parsers import set_deployment_parser
  from jina.parsers.ping import set_ping_parser
  from jina_cli.autocomplete import ac_table
  from jina_cli.export import api_to_dict
  from jina_cli.lookup import _build_lookup_table, lookup_and_print
  from tests.helper import _generate_pod_args
label_desc: Use image node_id 10 for calling a global function with example usage: test_help_exist() without return types