anchor.diff:     * The command line arguments.
      */
     final List<String> args;
  +
  +  /**
  +   * The path to the Dart SDK used during analysis.
  +   */
  +  String sdkPath;
   
     /**
      * The manager for the analysis server.
  
positive.code:   static const BINARY_NAME = 'dartdeps';
  
    /**
     * The name of the option used to print usage information.
     */
    static const String HELP_OPTION = 'help';
  
negative.code:       return null;
      }
      if (results[HELP_OPTION]) {
        printUsage(parser);
        return null;
      }
      sdkPath = results[DART_SDK_OPTION];
      if (sdkPath is! String) {
        print('Missing path to Dart SDK');
        printUsage(parser);
        return null;
      }
      Directory sdkDir = new Directory(sdkPath);
      if (!sdkDir.existsSync()) {
        print('Specified Dart SDK does not exist: $sdkPath');
        printUsage(parser);
        return null;
      }
  