Masked Image not saving photo

My code takes a photo and masks it on a imageview. However the mask effect is not saved with the photo. Just the standard photo is saved.

import UIKit

class ViewController: UIViewController, UINavigationControllerDelegate, UIImagePickerControllerDelegate {

@IBOutlet weak var imageView: UIImageView!
var imagePicker: UIImagePickerController!
 let maskView = UIImageView()

override func viewDidLoad() {
    super.viewDidLoad()
    maskView.image = UIImage(named: "mask")
    imageView.mask = maskView
    
}

override func viewDidLayoutSubviews() {
    super.viewDidLayoutSubviews()
    maskView.frame = imageView.bounds
}
func image(_ image: UIImage, didFinishSavingWithError error: Error?, contextInfo: UnsafeRawPointer) {
    if let error = error {
        // we got back an error!
        let ac = UIAlertController(title: "Save error", message: error.localizedDescription, preferredStyle: .alert)
        ac.addAction(UIAlertAction(title: "OK", style: .default))
        present(ac, animated: true)
    } else {
        let ac = UIAlertController(title: "Saved!", message: "Your altered image has been saved to your photos.", preferredStyle: .alert)
        ac.addAction(UIAlertAction(title: "OK", style: .default))
        present(ac, animated: true)
    }
}
@IBAction func takePhoto(_ sender: Any) {
    imagePicker =  UIImagePickerController()
    imagePicker.delegate = self
    imagePicker.sourceType = .camera
    present(imagePicker, animated: true, completion: nil)
}

@IBAction func savePhoto(_ sender: Any) {
    maskView.image = UIImage(named: "mask")
    imageView.mask = maskView
            UIImageWriteToSavedPhotosAlbum(maskView.image!, self, #selector(image(_:didFinishSavingWithError:contextInfo:)), nil)
}



func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : Any]) {
    imagePicker.dismiss(animated: true, completion: nil)
    imageView.image = info[UIImagePickerControllerOriginalImage] as? UIImage
}}