How does one disable third party keyboards in Swift?

Basically that's it, I haven't found a way to disable third party keyboard in my app, although I know it's possible 'cos I've seen it in apps like 1Password.

Any ideas?

Add this code in your AppDelegate

Swift 5

func application(_ application: UIApplication, shouldAllowExtensionPointIdentifier extensionPointIdentifier: UIApplication.ExtensionPointIdentifier) -> Bool {
    if extensionPointIdentifier == UIApplication.ExtensionPointIdentifier.keyboard {
        return false
    }
    return true
}

Swift 4:

func application(_ application: UIApplication, shouldAllowExtensionPointIdentifier extensionPointIdentifier: UIApplicationExtensionPointIdentifier) -> Bool {
    if extensionPointIdentifier == UIApplicationExtensionPointIdentifier.keyboard {
        return false
    }
    return true
}

Apple reference.