docs: function (items, options) {
              var removed = [];
  
              if (!_.isArray(items)) {
                  items = [items];
              }
              var item;
              for (var i = 0; i < items.length; i++) {
                  item = this.removeAt(this.indexOf(items[i]), options);
                  item && removed.push(item);
              }
              return removed;
          }