将Xcode更新为7.0后出错

Question

我在Swift中开发iOS应用程序。 当我将Xcode更新为7.0时，我在swiftyJSON中收到错误。

 static func fromObject(object: AnyObject) -> JSONValue? {
    switch object {
    case let value as NSString:
        return JSONValue.JSONString(value as String)
    case let value as NSNumber:
        return JSONValue.JSONNumber(value)
    case let value as NSNull:
        return JSONValue.JSONNull
    case let value as NSDictionary:
        var jsonObject: [String:JSONValue] = [:]
        for (k:AnyObject, v:AnyObject) in value {// **THIS LINE- error: "Definition conflicts with previous value"**
            if let k = k as? NSString {
                if let v = JSONValue.fromObject(v) {
                    jsonObject[k] = v
                } else {
                    return nil
                }
            }
        }

问题是什么？你能帮忙吗？