rem: return (this.fn == fn && this.obj == obj); 
add: if (obj) { return (this.fn == fn && this.obj == obj); } else { return (this.fn == fn); } 
context: YAHOO.util.Subscriber.prototype.contains = function(fn, obj) {    return (this.fn == fn && this.obj == obj);};
meta: 4707	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/4707/50c3492c4c3c825dbd3401e134a19ed46799c456/event-debug.js/buggy/www/resources/yui/event/event-debug.js