I'm looking to implement an image within the header of a collection view. This is the code that I have so far, but no header appears when I test. Am I missing something?

```
    func collectionView(_ collectionView: UICollectionView, viewForHeaderInSection section: Int) -> UIView? {
    let view = UIView()
    let image = UIImageView()
    image.frame = CGRect(x: collectionView.frame.width - 10 , y: 0, width: 20, height: 20)
    image.image = UIImage.init(named: "trophyCase")
    view.addSubview(image)
    return view
}

```