iOS Facebook App Delegate

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {

        FBSDKApplicationDelegate.sharedInstance().application(application, didFinishLaunchingWithOptions: launchOptions)

        return true
    }

    func application(_ app: UIApplication, open url: URL, options: [UIApplicationOpenURLOptionsKey : Any] = [:]) -> Bool {

        let handled: Bool = FBSDKApplicationDelegate.sharedInstance().application(app, open: url, sourceApplication: options [UIApplicationOpenURLOptionsKey.sourceApplication] as! String?, annotation: options[UIApplicationOpenURLOptionsKey.annotation])

        return handled
    }