             year following the receiver.
     */
     public func yearAfter() -> NSDate {
-        return TimeUnit().yearAfter(self)
+        return TimeUnit.yearAfter(self)
     }
 }

            hour following the receiver.
    */
    public func hourAfter() -> NSDate {
        return TimeUnit().hourAfter(self)
    }
    
    /**

            same month as the receiver.
    */
    public func endOfMonth() -> NSDate {
        return TimeUnit.endOfMonth(self)
    }
    
    /**
