anchor.diff:  
     Future deploy() async {
       await _detectOldVersion();
  +    if (stopFirst) {
  +      await _stopOldVersion();
  +    }
       await _gcloudDeploy();
       await _checkHealth();
       if (migrateTraffic) {
  
positive.code:   final String newVersion;
    final bool deleteOld;
    final bool migrateTraffic;
    String _oldVersion;
  
    _ServiceDeployer(
        this.service, this.newVersion, this.deleteOld, this.migrateTraffic)
        : project = Platform.environment['GCLOUD_PROJECT'] {
      if (project == null) {
        throw new StateError('GCLOUD_PROJECT must be set!');
  
negative.code: 
    for (String service in services) {
      print('\nDeploying $service...\n');
      await new _ServiceDeployer(
              service, newVersion, deleteOld, migrateTraffic, stopFirst)
          .deploy();
    }
  
  