anchor.diff:            abbr: 'l',
             negatable: false,
             help: 'cluster by label')
  +      ..addFlag('skip-uninteresting-labels',
  +          defaultsTo: false,
  +          abbr: 's',
  +          negatable: true,
  +          help: 'skip uninteresting labels (e.g., \'cla: yes\')')
         ..addFlag('authors',
             defaultsTo: false,
             abbr: 'a',
  
positive.code:       for (var label in toRemove) clusters.remove(label);
      }
  
      print(clusters.toMarkdown(
          sortType: (opts.alphabetize
              ? ClusterReportSort.byKey
  
negative.code:   if (opts.exitCode != null) exit(opts.exitCode);
    var keys = Set<String>();
  
    final repos = opts.prs ? ['flutter', 'engine', 'plugins'] : ['flutter'];
    final labelsToSkip = ['cla: yes', 'waiting for tree to go green'];
  
    final token = Platform.environment['GITHUB_TOKEN'];
    final github = GitHub(token);
  