code: function (query, options) {
              options.$itemsCount = undefined;
  
              var collection = new this.factory(null, options);
              collection.$context = this.$context;
  
              return collection;
          }
docs: This method creates internally a filtered collection
  @param {js.data.Query} query
  @param {Object} options
  @returns {js.data.Collection}
  @private