code: function () {
        var fileContent = self._readFileSync();
  
        if (fileContent.instances && fileContent.instances[this._id]) {
          delete fileContent.instances[this._id];
  
          self._writeFileSync(fileContent);
        }
        else {
          debug('deleteSync instance %s not exists for app: %s', this._id, self._app);
        }
      }
docs: Delete the instance