anchor.diff:    print("The 'download' subcommand downloads all discovery documents. "
         'It takes the following options:');
     print('');
  -  print(downloadCommandArgParser().usage);
  +  print(_downloadCommandArgParser().usage);
     print('');
     print("The 'run_config' subcommand downloads discovery documents and "
         'generates one or more API packages based on a configuration file. '
         'It takes the following options:');
     print('');
  -  print(runConfigCommandArgParser().usage);
  +  print(_runConfigCommandArgParser().usage);
     exit(1);
   }
   
   Future<void> main(List<String> arguments) async {
  -  final parser = globalArgParser();
  -  final options = parseArguments(parser, arguments);
  +  final parser = _globalArgParser();
  +  final options = _parseArguments(parser, arguments);
     final commandOptions = options.command!;
     final subCommands = ['download', 'generate', 'run_config'];
   
     if (options['help'] as bool) {
  -    dieWithUsage();
  +    _dieWithUsage();
     } else if (!subCommands.contains(commandOptions.name)) {
  -    dieWithUsage('Invalid command');
  +    _dieWithUsage('Invalid command');
     }
   
     switch (commandOptions.name) {
  
positive.code: import 'package:args/args.dart';
  import 'package:googleapis_generator_dependency/googleapis_generator.dart';
  
  ArgParser downloadCommandArgParser() => ArgParser()
    ..addOption('output-dir',
        abbr: 'o',
        help: 'Output directory of discovery documents.',
        defaultsTo: 'googleapis-discovery-documents');
  
  ArgParser runConfigCommandArgParser() => ArgParser()
    ..addCommand('download')
    ..addCommand('generate')
    ..addOption(
  
negative.code:     case 'run_config':
        if (commandOptions.command == null ||
            !['download', 'generate'].contains(commandOptions.command!.name)) {
          _dieWithUsage('The `run_config` command has only the two subcommands: '
              '`download` and `generate`.');
        }
  
  