can not parse nested dictionary : i want to parse this son data but can't make it. please suggest something to make this to deadlines.
json data is like
[jsondata][1]        `

i have tried a lot! my code is 

    session.dataTask(with: request, completionHandler:{( data , response , error) -> Void in
        if let data = data {
                if let jsonObj = try? JSONSerialization.jsonObject(with: data , options: .allowFragments) as! Any {
            print(jsonObj)
                    if  let postdata = (jsonObj as AnyObject).value(forKey: "postdata") {
                        print(postdata)
                        //if let something = postdata["best_before"] as? NSDictionary{
                           // print(something) 


  [1]: https://i.stack.imgur.com/lkBEG.png