class TabsViewController: DSTabsViewController<HeaderView> {

 init() {
  super.init(viewControllers: [
   UIViewController(),
   UIViewController()
  ])
 }

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

}

let stackView = UIStackView()
 .addInRootView(view)
 .setTopAnchor(anchor: topLayoutGuide.bottomAnchor, marge: 10)
 .setRightAnchor(anchor: view.rightAnchor, marge: 10)
 .setBottomAnchor(anchor: bottomLayoutGuide.topAnchor, marge: 10)
 .setLeftAnchor(anchor: view.leftAnchor, marge: 10)

let side: CGFloat = 70

label1.addInRootView(stackView)
 .setSize(width: side, height: side)
 .setTopAlignment()
 .setCenterX()