@return Returns the index of the last occurrence, or <code>-1</code> if the element doesn't exist.
        */
        public function indexOf(item:*, fromIndex:int = 0):int {
            return this._collection.indexOf(item, fromIndex);
        }
        
        /**
            Determines if this list contains no elements.
            
            @return Returns <code>true</code> if the list contains no items; otherwise <code>false</code>.
        */
        public function isEmpty():Boolean {
           