BottomSheetPresentationController_6.swift

extension BottomSheetPresentationController {
    private func setupInteraction() {
        guard let presentedView = presentedView else {
            return
        }
        
        func addGestureIfNeeded(_ gesture: UIGestureRecognizer, to view: UIView, delegate: UIGestureRecognizerDelegate? = nil) {
            if let recognizers = view.gestureRecognizers, recognizers.contains(gesture) {
                return
            }
            gesture.delegate = delegate
            view.addGestureRecognizer(gesture)
        }
                
        addGestureIfNeeded(panGesture, to: presentedView, delegate: self)
        addGestureIfNeeded(tapGestureToDismiss, to: dimmedBackgroundView)
    }
}