code: function(response) {
        this.set('fetchSuccess', false);
        this.set('fetchedOnce', true);
        if (this.__shouldTriggerFetchedEvent(response)) {
          this.trigger('fetched', {
            status: FETCHED_STATUSES.FAILURE,
            response: response
          });
          this.data.trigger('fetched', {
            status: FETCHED_STATUSES.FAILURE,
            response: response
          });
          if (response && response.emptyIds) {
            this.__firstEmptyFetchedTriggered = true;
          }
        }
        this.trigger('fetched:ids');
        this.data.trigger('fetched:ids');
        return response;
      }
docs: Triggers a 'fetched' event with the payload { status: 'failed' } when the fetch fails.
  @method __fetchFailed
  @param [response] {Object} the response from the server.
  @param [response.skipObjectRetrieval=false] {Boolean} if we retrieved objects, then trigger fetch event.
  @param [response.forceFetchedEvent=false] {Boolean} if true then trigger fetch no matter what.
  @param [response.emptyIds=false] {Boolean} true if were are no ids retrieved.  False otherwise.
  @private