UIPageViewController programmatically swift 4 - ios

Question

I wrote this code that checked several times I can not understand where I'm wrong.
I can not see my page..
but I see a black background with the 3 dots of pageControl.
I checked several times, I set the yellow background on the first page..
can you give me a hand?
I have 3-4 more files in which I declare the pages and their layout
Result
final class IntroViewController: UIPageViewController, UIPageViewControllerDelegate {
var introRouter: IntroRouter?
var pages = [UIViewController]()
let pageControl = UIPageControl()
override var preferredStatusBarStyle: UIStatusBarStyle {
return .lightContent
// self.delegate = self
let initialPage = 1
let page1 = ViewController1()
let page2 = ViewController2()
let page3 = ViewController3()
let page4 = ViewController4()
self.pages.append(page1)
self.pages.append(page2)
self.pages.append(page3)
self.pages.append(page4)
setViewControllers([pages[initialPage]], direction: .forward, animated: true, completion: nil)
self.pageControl.frame = CGRect()
self.pageControl.currentPageIndicatorTintColor = UIColor.black
self.pageControl.pageIndicatorTintColor = UIColor.lightGray
self.pageControl.numberOfPages = self.pages.count
self.pageControl.currentPage = initialPage
self.view.addSubview(self.pageControl)
self.pageControl.translatesAutoresizingMaskIntoConstraints = false
self.pageControl.bottomAnchor.constraint(equalTo: self.view.bottomAnchor, constant: -5).isActive = true
self.pageControl.widthAnchor.constraint(equalTo: self.view.widthAnchor, constant: -20).isActive = true
self.pageControl.heightAnchor.constraint(equalToConstant: 20).isActive = true
self.pageControl.centerXAnchor.constraint(equalTo: self.view.centerXAnchor).isActive = true
}
override func viewDidLoad() {
super.viewDidLoad()
setupUI()
arrangeSubviews()
}
override init(transitionStyle style: UIPageViewControllerTransitionStyle, navigationOrientation: UIPageViewControllerNavigationOrientation, options: [String : Any]? = nil) {
super.init(transitionStyle: style, navigationOrientation: navigationOrientation, options: options)
}
func setRouter(introRouter: IntroRouter) {
self.introRouter = introRouter
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
}
private extension IntroViewController {
func IntroViewController(_ IntroViewController: UIPageViewController, viewControllerBefore viewController: UIViewController) -> UIViewController? {
if let viewControllerIndex = self.pages.index(of: viewController) {
if viewControllerIndex == 0 {
// wrap to last page in array
return self.pages.last
} else {
// go to previous page in array
return self.pages[viewControllerIndex - 1]
}
}
return nil
}
func IntroViewController(_ IntroViewController: UIPageViewController, viewControllerAfter viewController: UIViewController) -> UIViewController? {
if let viewControllerIndex = self.pages.index(of: viewController) {
if viewControllerIndex < self.pages.count - 1 {
// go to next page in array
return self.pages[viewControllerIndex + 1]
} else {
// wrap to first page in array
return self.pages.first
}
}
return nil
}
func IntroViewController(_ IntroViewController: UIPageViewController, didFinishAnimating finished: Bool, previousViewControllers: [UIViewController], transitionCompleted completed: Bool) {
// set the pageControl.currentPage to the index of the current viewController in pages
if let viewControllers = IntroViewController.viewControllers {
if let viewControllerIndex = self.pages.index(of: viewControllers[0]) {
self.pageControl.currentPage = viewControllerIndex
}
}
}
func setupUI() {
pageControl.do {
$0.numberOfPages = 4
$0.currentPage = 1
$0.pageIndicatorTintColor = .lightGray
$0.currentPageIndicatorTintColor = Theme.Colors.white
}
}
func arrangeSubviews() {
view.addSubview(pageControl)
}
}