         let dic = NSMutableDictionary()
         for (k, v) in self {
             // 第一步序列化key
-            if let k = _serialize(k) as? NSCopying {
+            if let k = _serialize(k) {
                 // 只支持转换为`NSString`
                 guard let k = NSString.deserialize(k) else {
                     continue

/// - returns: 如果返回nil, 反序列化失败
///
public func deserialize<T>(o: AnyObject) -> T?  {
    return _deserialize(o)
}

///

    public static func deserialize(o: AnyObject) -> UInt? {
        // 如果可以的话转换一下..
        if let number = NSNumber.deserialize(o) {
            return number.unsignedLongValue
        }
        return nil
    }
