code: def verify_binary(flag_name, process_args=None):
      
      if process_args is None:
          process_args = []
  
      path = getattr(FLAGS, flag_name)
      if not path:
          logging.error('Flag %r not set' % flag_name)
          sys.exit(1)
  
      with open(os.devnull, 'w') as dev_null:
          try:
              subprocess.check_call(
                  [path] + process_args,
                  stdout=dev_null,
                  stderr=subprocess.STDOUT)
          except:
              logging.exception('--%s binary at path %r does not work',
                                flag_name, path)
              sys.exit(1)
docs: Exits the program if the binary from the given flag doesn't run.
  
      Args:
          flag_name: Name of the flag that should be the path to the binary.
          process_args: Args to pass to the binary to do nothing but verify
              that it's working correctly (something like "--version") is good.
              Optional. Defaults to no args.
  
      Raises:
          SystemExit with error if the process did not work.