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

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

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