code: function (contentIndex) {
      var itemViewClass, childView;
  
      itemViewClass = this.itemViewForIndex(contentIndex);
      childView = this.createChildView(itemViewClass);
      this.pushObject(childView);
    }
docs: @private
  
  Returns a new item view. Takes `contentIndex` to set the context
  of the returned view properly.
  
  @param {Number} contentIndex item index in the content array
  @method _addItemView