我在Swift 2.3到Swift 3.0中遇到了一个不寻常的问题。一旦我将代码从2.3转换到3.0，我就遇到了这个问题：“对成员”Subscribe“的引用不明确，
代号为：

dynamic func onDataNotification(notification: NSNotification) {
        var data = notification.userInfo as! Dictionary<NSString, ARoutedMessage>
        if let packet = data[AEnginePacketDataKey] as? AEngineMessage,
        currentDevice = self.currentDevice() {
            if packet.messageId == MessageId.message && currentDevice.isDevice() {
// Some code 
            }
        }
    }

在let packet = data[AEnginePacketDataKey]上获取错误，因为对成员'Subscribe'的引用不明确，我不明白为什么？。其他：

// String 
extern NSString *AEnginePacketDataKey;

//ARoutedMessage Class
@interface ARoutedMessage : NSObject
@property NSMutableArray *payloadParameters;
@end

//AEngineMessage Class
@interface AEngineMessage : ARoutedMessage
@property (readonly)MessageId messageId;
- (id) initWithMessageId:(MessageId) mId;
@end

请帮帮我。