Unable to remove child viewcontroller after Navigation

Question

I have added a child viewcontroller to VC1. On tapping a button in child viewcontroller , I am pushing to another viewcontroller , VC2. On tapping back button in VC2 , I need to remove the child viewcontroller but I m unable to do it.Can u pls help me ?

override func viewDidDisappear(_ animated: Bool) {

        let controller = storyboard!.instantiateViewController(withIdentifier: "PopupViewController") as! PopupViewController
        controller.willMove(toParentViewController: nil)
        controller.view.removeFromSuperview()
        controller.removeFromParentViewController()
 }

Answer 1

I added the following in VC1 and it solved my problem

override func viewWillDisappear(_ animated: Bool) {

    for controllers in self.childViewControllers
    {
        controllers.willMove(toParentViewController: nil)
        controllers.view.removeFromSuperview()
        controllers.removeFromParentViewController()
    }

}