UICollectionView cellForItem not being called

I am implementing UICollectionView (collectionView) in base ViewController my collection view needs to fetch 5 cells as in codeofItemInSection. The CollectionView is displayed and the numofItemInSection function is called, but the cellForItemAt function is not called, so the collection view is empty.

import UIKit


private let reuseIdentifier = "Cell"



class TestViewController: UIViewController, UICollectionViewDataSource, UICollectionViewDelegate{

    lazy var collectionView : UICollectionView = {
        let layout = UICollectionViewFlowLayout()
        let cv = UICollectionView(frame: .zero, collectionViewLayout: layout)
        cv.translatesAutoresizingMaskIntoConstraints = false
        cv.delegate = self
        cv.dataSource = self
        return cv
    }()

    override func viewDidLoad() {
        super.viewDidLoad()

        // Register cell classes
        self.collectionView.register(UICollectionViewCell.self, forCellWithReuseIdentifier: reuseIdentifier)

        collectionView.backgroundColor = .white
        navigationItem.title = "test"

        setupViews()
    }

    func setupViews(){
        view.addSubview(collectionView)

        collectionView.leftAnchor.constraint(equalTo: view.leftAnchor).isActive = true
        collectionView.rightAnchor.constraint(equalTo: view.rightAnchor).isActive = true
        collectionView.heightAnchor.constraint(equalToConstant: 60).isActive = true
        collectionView.topAnchor.constraint(equalTo: topLayoutGuide.bottomAnchor).isActive = true
    }

     func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return 5
    }

     func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: reuseIdentifier, for: indexPath)
        // Configure the cell

        cell.backgroundColor = .red

        return cell
    }


}