code: def _MockSubprocess4(
      cmd,
  ):  # pylint: disable=invalid-name, unused-argument
      list_dags_output_path = os.path.join(
          _testdata_dir, "test_airflow_list_dags_output.txt"
      )
      with open(list_dags_output_path, "rb") as f:
          list_dags_output = f.read()
      return list_dags_output
  
imports: import json
  import os
  import subprocess
  import sys
  from unittest import mock
  import click
  import tensorflow
  from tfx.dsl.components.base import base_driver
  from tfx.dsl.io import fileio
  from tfx.tools.cli import labels
  from tfx.tools.cli.handler import airflow_handler
  from tfx.utils import io_utils
  from tfx.utils import test_case_utils
label_desc: Use image node_id 4 for calling a global function with example usage: _MockSubprocess4(cmd) and returns: list_dags_output