     /*!
         Create a Foundation object from JSON data.
      */
-    public func parseJSON(_ block:(AnyObject,NSError?)->Void){
+    public func parseJSON(_ block:(AnyObject?,NSError?)->Void){
         var obj:AnyObject = "not a json"
         var theError:NSError?
         do{

            if let _ = self.jsonHandler{
                self.data.parseJSON({ (object, error) in
                    OperationQueue.main({
                        self.jsonHandler?(anyObject:object)
                    })
                })
                

}
public typealias progressHandler = ((countOfBytesReceived: Int64 ,countOfBytesExpectedToReceive: Int64) -> Void)
public typealias completionHandler = ((data:Data?, response:URLResponse?, error:NSError?) -> Swift.Void)
public typealias jsonHandler = (anyObject:AnyObject?,error:NSError?)->Void
public typealias imageHandler = (image:UIImage?,error:NSError?)->Void
public class WTURLSessionTask:NSObject,URLSessionDataDelegate{
    //网址凭据
