Attribute 'private' can only be used in a non-local scopeというエラー

import Photos
import PhotosUI
import UIKit

class MyCell: UICollectionViewCell {
    let imageView = UIImageView()
    
    override init(frame:CGRect) {
        super.init(frame: frame)
        addSubview(imageView)
    }
    
    required init?(coder: NSCoder) {
        fatalError()
    }
    
    override func layoutSubviews() {
        super.layoutSubviews()
        imageView.frame = bounds
    }
}
class ViewController: UIViewController, PHPickerViewControllerDelegate, UICollectionViewDataSource {
    func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        <#code#>
    }
    
    func picker(_ picker: PHPickerViewController, didFinishPicking results: [PHPickerResult]) {
        <#code#>
    }
    
    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        <#code#>
    }
    
    
    
    private let collectionView: UICollectionView = {
        let layout = UICollectionViewFlowLayout()
        
        let c = UICollectionView(frame: .zero, collectionViewLayout: layout)
        c.register(MyCell.self, forCellWithReuseIdentifier: "cell")
        return c
    }()

    override func viewDidLoad() {
        super.viewDidLoad()
        view.addSubview(collectionView)
        collectionView.dataSource = self
        collectionView.frame = view.bounds
        title = "New Photo Picker"
        navigationItem.rightBarButtonItem = UIBarButtonItem(barButtonSystemItem: .add, target: self, action: #selector(didTapAdd))
    }
    @objc private func didTapAdd() {
        var config = PHPickerConfiguration(photoLibrary: .shared())
        config.selectionLimit = 3
        config.filter = .images
        let vc = PHPickerViewController(configuration: config)
        vc.delegate = self
        present(vc, animated: true)
        

        func picker(_ picker: PHPickerViewController, didFinishPicking results: [PHPickerResult]) {
            picker.dismiss(animated: true, completion: nil)
            
            results.forEach { results in
                results.itemProvider.loadObject(ofClass: UIImage.self) { reading, error in
                    guard let image = reading as? UIImage, error == nil else{
                        return
                }
                    print(image)
}
        
        
    }
        }
        
        private let images = [UIImage]()
        
        
        func collectionView(_ collectionView: UICollectionView, numberOfItemInSection section: Int) -> Int { return images.count
    }
        func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell { guard let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "cell", for: indexPath) as? MyCell else { fatalError()}
            
            cell.imageView.image = images[indexPath.row]
            
            return cell
}
    }
}

Xcode初心者です。今写真のアプリ作ろうと思っています。
private let images = UIImageに__Attribute 'private' can only be used in a non-local scopeというエラー__が出てどうしてもこのエラーが無くなりません
解決方法を教えていただきたいです。