docs: function(propertyName) {
        var privateCollection = this.privateCollection;
        if (!this.parentBehavior.returnSingleResult) {
          if (_.isString(propertyName)) {
            return privateCollection.pluck(propertyName);
          } else {
            return privateCollection.toJSON();
          }
        }
  
        var singleResultModel = this.getModel();
        if (singleResultModel) {
          if (_.isString(propertyName)) {
            return singleResultModel.get(propertyName);
          }
          return singleResultModel.toJSON();
        }
      }