How to display items in a random order

function tifd_feedzy_feed_items_ramdom( $items, $feedURL ){
    if( 'http://themeisle.com/feed' == $feedURL ) {
        shuffle ( $items );
    }
    return $items;
}
add_filter('feedzy_feed_items', 'tifd_feedzy_feed_items_ramdom', 9, 2);