code: function() {
        var staleItemViews = [];
        var modelsWithViews = _.clone(this.__modelToViewMap);
        _.each(this.modelsToRender(), function(model) {
          var itemView = this.getItemViewFromModel(model);
          if (itemView) {
            delete modelsWithViews[model[this.__modelId]];
          }
        }, this);
        _.each(modelsWithViews, function(viewId, modelId) {
          var itemView = this.getTrackedView(viewId);
          if (itemView) {
            staleItemViews.push({ view: itemView, modelId: modelId });
          }
        }, this);
        return staleItemViews;
      }
docs: Gets all item views that have models that are no longer tracked by modelsToRender
  @method __getStaleItemViews
  @return {Array} An array of information about stale items. Each object has a 'view' and 'modelId' field
  @private