Ambiguous reference to member subscript (p.323) Kindle Edition

In the method photosFromJSONData(_:), I am getting the error message:

ambiguous reference to member subscript

specifically on the line
photos = jsonDictionary[“photos”] as? [String:AnyObject],

A snippet of the surrounding code is shown below

guard let jsonDictionary = jsonObject as? [NSObject:AnyObject],
photos = jsonDictionary[“photos”] as? [String:AnyObject],
photosArray = photos[“photo”] as? [[ String:AnyObject]]

Replace NSObject with String in the first optional cast

Thank you, it worked

I got stuck with this too - thanks