Replace child view controller segue

ReplaceSegue.swift

class ReplaceSegue: UIStoryboardSegue {
    
    override func perform() {
        let containerViewController = sourceViewController
        if containerViewController.childViewControllers.count == 0 {
            return;
        }
        
        let sourceVC = containerViewController.childViewControllers[0]
        containerViewController.addChildViewController(destinationViewController)
        destinationViewController.view.frame = sourceVC.view.frame
        sourceVC.willMoveToParentViewController(nil)
        
        
        containerViewController.transitionFromViewController(sourceVC, toViewController: destinationViewController, duration: 0.5, options: .TransitionCrossDissolve, animations: { () -> Void in
            }, completion: { (animated) -> Void in
                sourceVC.removeFromParentViewController()
                self.destinationViewController.didMoveToParentViewController(containerViewController)
        })
    }
}