如您所見(jiàn)，我正在接收一個(gè)JSON文件，使用SwiftyJSON對(duì)其進(jìn)行解析，并嘗試返回totalTime，但是它不允許我這樣做。我該怎么做呢？func googleDuration(origin: String, destination: String) -> Int{    // do calculations origin and destiantion with google distance matrix api    let originFix = origin.stringByReplacingOccurrencesOfString(" ", withString: "+", options: NSStringCompareOptions.LiteralSearch, range: nil);    let destinationFix = destination.stringByReplacingOccurrencesOfString(" ", withString: "+", options: NSStringCompareOptions.LiteralSearch, range: nil);    let urlAsString = "https://maps.googleapis.com/maps/api/distancematrix/json?origins="+originFix+"&destinations="+destinationFix;    println(urlAsString);    let url = NSURL(string: urlAsString)!    let urlSession = NSURLSession.sharedSession()    let task = urlSession.dataTaskWithURL(url, completionHandler: {data, response, error -> Void in        if error != nil {            // If there is an error in the web request, print it to the console            println(error.localizedDescription)        }        println("parsing JSON");        let json = JSON(data: data);        if (json["status"].stringValue == "OK") {            if let totalTime = json["rows"][0]["elements"][0]["duration"]["value"].integerValue {                println(totalTime);            }        }    })    task.resume();}