UICollectionView programmatically

gistfile1.txt

    lazy var collectionView: UICollectionView = {
        let layout = UICollectionViewFlowLayout()
        layout.itemSize = CGSize(width: 140, height: 250)
        layout.scrollDirection = .horizontal
        let collection = UICollectionView(frame: self.view.frame, collectionViewLayout: layout)
        collection.translatesAutoresizingMaskIntoConstraints = false
        collection.register(GifCollectionViewCell.self, forCellWithReuseIdentifier: cellId)
        collection.backgroundColor = UIColor.CustomColors.spotifyDark
        collection.bounces = true
        collection.alwaysBounceHorizontal = true
        collection.alwaysBounceVertical = false
        collection.delegate = self
        collection.dataSource = self
        return collection
    }()