I'm working on setting push notifications through Firebase for my application. **Swift 3**

In the AppDelegate under didFinishLaunchingOptions, I am running into an error on this line: 

**Argument labels '(forTypes:, categories:)' do not match any available overloads**

```
let notificationSettings = UIUserNotificationSettings(forTypes: notificationTypes, categories: nil)

```

**Code:**

```
class AppDelegate: UIResponder, UIApplicationDelegate {

var window: UIWindow?

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
    // Override point for customization after application launch.

    FIRApp.configure()

    FIRDatabase.database().persistenceEnabled = true

    SKCache.sharedCache.imageCache = CustomImageCache()

    let notificationTypes : UIUserNotificationType = [UIUserNotificationType.alert, UIUserNotificationType.badge, UIUserNotificationType.sound]
    let notificationSettings = UIUserNotificationSettings(forTypes: notificationTypes, categories: nil)

    application.registerForRemoteNotifications()
    application.registerUserNotificationSettings(notificationSettings)

```

Thanks!