     func getPhoto(from url: String/*, completion: ((UIImage?) -> Void)*/) {
         var image: UIImage? = nil
         if cache[url] == nil {
-            print("1")
             //cache[url] = image
             URLSession.shared.dataTask(with: NSURL(string: url)! as URL, completionHandler: { (data, _, _) -> Void in // previously (data, response, error)
                 DispatchQueue.main.async(execute: { () -> Void in

        //completion(image)
    }
}


// wywolanie w ViewDidLoad() klasy Gallery View Controller:
// PhotoManager.shared.getPhoto(from: "https://static.pexels.com/photos/347721/pexels-photo-347721.jpeg")

                })
            }).resume()
        } else if self.cache[url] != nil {
            image = self.cache[url]
        } else {
            print("Error")
