How to exclude an element from being dragged in sortable list?

How can I exclude an element from sortable list? For instance, there is an element with class name 'note' that I don't want to be draggable?

    <ul class="sortable">

            <li id="item_3">Item 3</li>
            <li id="item_4">Item 4</li>
            <li id="item_5">Item 5</li>

            <p class="note">This is a note only</p> 
   </ul>

jquery ui sortable, jquery not obviously does not work...

$(function() {
    $( ".sortable:not(.note)" ).sortable(
    }).disableSelection();
});