anchor.diff:  
     parser
       ..addFlag(
  +      argVersion,
  +      negatable: false,
  +      help: 'Prints the DevTools version.',
  +    )
  +    ..addFlag(
         argVerbose,
         negatable: false,
         abbr: 'v',
  
positive.code:     print('Dart DevTools version ${await _getVersion()}');
      print('');
      _printUsage(verbose);
      return null;
    }
  
  
negative.code:   String? customDevToolsPath,
  }) async {
    final help = args[argHelp];
    final bool version = args[argVersion];
    final bool machineMode = args[argMachine];
    // launchBrowser defaults based on machine-mode if not explicitly supplied.
    final bool launchBrowser =
  