 
 fileprivate class UNDSideSlidePresentationController: UIPresentationController {
     
-    var configureModel: UNDSideSlideTransitioningConfigModel
+    var configureModel: UNDSideSlideTransitioningConfigModel?
     var dimmingView: UIView!
     var panGestureRecognizer: UIPanGestureRecognizer?
     var dismissTapGestureRecognizer: UITapGestureRecognizer?

        self.dimmingView.addSubview(self.presentedViewController.view)
        self.presentedViewController.transitionCoordinator?.animate(alongsideTransition: { [unowned self] (_) in
            self.dimmingView.alpha = 1
            if self.configureModel.shouldShrinkPresentingViewController {
                self.presentingViewController.view.transform = CGAffineTransform(scaleX: 0.9, y: 0.9)
            }
        }, completion: nil)

    // Mark: - UIPresentationController
    override var frameOfPresentedViewInContainerView: CGRect {
        if let unWrappedContainerView = self.containerView {
            if let unWrappedConfigureModel = self.configureModel {
                return CGRect(origin: unWrappedConfigureModel.preferredOriginPoint(from: unWrappedContainerView)
                              , size: unWrappedConfigureModel.preferredSize)
            } else {
                return unWrappedContainerView.bounds
            }
        } else {
            return CGRect.zero
        }
