Not getting any response from slide on accordion menu

Hi everyone I am trying to get my accordion menu to work but I do not get a response from it and have no errors! Am I calling the objects right?

    $(function () {

//
// Set up a click event handler for clicked <li>
//
    $('#accordion li').click(function() {

    // find first ul that is a child of this (the clicked <li>)
    var $nextUL = $(this).children('ul:first-child');

    // Select all siblings of the clicked <li> and then 
    // select any direct children <ul>'s 
    // that are visible - this is so we can close any visible
    // <ul> before opening the <ul> for the clicked <li>
    var $visibleSiblings = $(this).siblings().children('ul:visible');

    // If any other <ul>s are visible, slide the visible <ul>
    // up and then, after the slide up is complete, slide down 
    // the clicked <li>'s <ul> into view
    if ($visibleSiblings.length > 0) {

        $visibleSiblings.slideDown('normal');

        $nextUL.fadeIn('normal');

    } else {
        // either no <ul>s were open (open the clicked item)
        // or the user clicked on the currently open one so close it
        $nextUL.slideToggle('normal');
    }
        });
    });