code: function (item/*, index*/) {
  		var old = item;
  		var Constructor;
  		if (!(item instanceof ok.Base)) {
  			Constructor = this.getConstructor(item);
  			item = new Constructor(item);
  		}
  		var identified = this.identify(item);
  		if (identified) {
  			identified.set(old);
  		}
  		else {
  			var index = this.findInsertIndex(item);
  			this.items.insert(index + 1, item);
  		}
  	}
docs: Add a single item to this collection
  @param {*} item Item to add to collection
  @param {int} index Position to add the item
  @fires add