Swift Images to Cache - swift

Question

I am parsing data and checking if an image is in cache. If yes, set it, if not set it to default and send it to cache.
The part that sends it to cache keeps giving nil ???
Any help would be appreciated
Pic_STR = "https://myserver/Pictures/" + Pic + ".jpg"
let url = URL(string: Pic_STR)
if let imageFromCache = imageCache.object(forKey: Pic_STR as AnyObject) as? UIImage {
data.photo = imageFromCache
return
} else {
data.photo = UIImage(named: "Default")
let imageCache = NSCache<NSString, AnyObject>()
URLSession.shared.dataTask(with: url!) { data, response, error in
guard let data = data, error == nil else { return }
let imageToCache = UIImage(data: data)
imageCache.setObject(imageToCache!, forKey: self.Pic_STR as NSString)
//self.image = imageToCache
}.resume()
}

Answer 1

After much experiminting I finally found a solution. I am sure it could be improved, but it works. I would prefer to use an extension, but can't figure out how.
struct imageData {
let image: UIImage?
let name: String?
}
var newImage = UIImage()
var myImages = [imageData]()
let imageString= "https://myserver/Pictures/" + Pic + ".jpg"
let imageURL = URL(string: imageString)
CON2 = false
for pics in myImages {
if pics.name == Pic {
data.photo = pics.image
CON2 = true
}
}
if CON2 == false {
let data2 = try? Data(contentsOf: imageURL!)
if let imageData = data2 {
newImage = UIImage(data: imageData)!
}
let newData = imageData(image: newImage, name: Pic) as imageData
myImages += [newData]
data.photo = newImage
}