anchor.diff:  
   main(List<String> args) async {
     final parser = new ArgParser();
  +  parser.addFlag("automated-approver",
  +      help: "Record the approval as done by an automated process.",
  +      negatable: false);
     parser.addMultiOption("bot",
         abbr: "b",
         help: "Select the bots matching the glob pattern [option is repeatable]",
         splitCommas: false);
     parser.addFlag("help", help: "Show the program usage.", negatable: false);
  +  parser.addFlag("failures-only",
  +      help: "Approve failures only.", negatable: false);
     parser.addFlag("list",
         abbr: "l", help: "List the available bots.", negatable: false);
     parser.addFlag("no",
  
positive.code:       }
        final name = result["name"];
        final test = new Test(bot, name, result, approvedResult, flakiness);
        tests.add(test);
      }
      // If preapproving and the CL has introduced new tests, add the new tests
  
negative.code:       negatable: false);
    parser.addOption("preapprove",
        abbr: "p", help: "Preapprove the new failures in a gerrit CL.");
    parser.addFlag("successes-only",
        help: "Approve successes only.", negatable: false);
    parser.addFlag("verbose",
        abbr: "v", help: "Describe asynchronous operations.", negatable: false);
    parser.addFlag("yes",
  