The source code

    /*!
     * Ext JS Library 3.4.0
     * Copyright(c) 2006-2011 Sencha Inc.
     * licensing@sencha.com
     * http://www.sencha.com/license
     */
    (function(){
    	var libFlyweight;

    	function fly(el) {
            if (!libFlyweight) {
                libFlyweight = new Ext.Element.Flyweight();
            }
            libFlyweight.dom = el;
            return libFlyweight;
        }