How to access and set WKWebview configuration from appDelegate in ios?

func application(_ application: UIApplication, willFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey : Any]? = nil) -> Bool {
        (window?.rootViewController as? CAPBridgeViewController)?.loadViewIfNeeded();
        (window?.rootViewController as? CAPBridgeViewController)?.webView?.backgroundColor = UIColor.black;
        return true
    }