code: function(options) {
              options = options || {};
              options.idsToFetch = options.idsToFetch || this.trackedIds;
              options.setOptions = options.setOptions || {remove: false};
              return this.__loadWrapper(function() {
                if (options.idsToFetch && options.idsToFetch.length) {
                  return parentInstance.fetchByIds(options);
                } else {
                  return $.Deferred().resolve().promise();
                }
              });
            }
docs: Will force the cache to fetch just the registered ids of this collection
  @method requesterMixin.fetch
  @param [options] - argument options
  @param [options.idsToFetch=collectionTrackedIds] {Array} - A list of request Ids, will default to current tracked ids
  @param [options.setOptions] {Object} - if a set is made, then the setOptions will be passed into the set method
  @return {Promise} promise that will resolve when the fetch is complete