Parse.com - PFUser.logInWithUsernameInBackground() hangs

Question

I'm having a problem with some code that I copied almost directly from the Parse docs. I think it is because something in the newer versions of Swift broke the code. The docs say that you can override initialize() in NSObject, but when I do that the program just hangs when I try to execute PFUser.loginWithUsernameInBackground().

The code that I've written is attached. Even if I don't instantiate a Movie, it crashes once the initialize() code is uncommented.

I really could use some help, as I've relied on this code (without, I confess, a 100% understanding of its significance).

class Movie:PFObject, PFSubclassing {

@NSManaged var title:String
@NSManaged var year:Int
 //   @NSManaged var producer:Producer

//    override class func initialize() {
//        struct Static {
//            static var onceToken : dispatch_once_t = 0;
//        }
//        dispatch_once(&Static.onceToken) {
//            self.registerSubclass()
//        }
//    }
//    
    static func parseClassName() -> String {
        return "Movie"
    }


}