CollectionViewFlowLayout.swift

extension TitledCollectionView {
    
    class Layout: UICollectionViewFlowLayout {
        static let heightConstant: CGFloat = 150
        
        override func prepare() {
            super.prepare()
            guard let collectionView = collectionView else { return }
            // TODO: why -13 to make the size even? section insets?
            itemSize = CGSize(width: collectionView.frame.width / 3 - 13, height: Self.heightConstant - 40)
            scrollDirection = .horizontal
            sectionInset = UIEdgeInsets(top: 0, left: 10, bottom: 0, right: 10)
        }
    }
    
}