di-6.swift

class StoreViewController: UIViewController {
    typealias Factory = BooksViewControllerBuilder & VideosViewControllerBuilder
    private let factory: Factory

    init(_ factory: Factory) {
        self.factory = factory
        super.init(nibName: nil, bundle: nil)
    }

    required init?(coder aDecoder: NSCoder) { fatalError("init(coder:) has not been implemented") }

    override func viewDidLoad() {
        super.viewDidLoad()

        // Add booksViewController
        let booksViewController: BooksViewContoller = factory.build()
        add(child: booksViewController)

        // Add videosViewController 
        let videosViewController: VideosViewController = factory.build()
        add(child: videosViewController)
    }

    func add(child controller: UIViewController) {
        //... Add child view contollers
    }
}