GoogleMobileAds cannot be implemented

I want to implement GoogleMobileAds to display ads, but it doesn't work.
I managed to check GoogleMobileAds settings myself.

In my opinion

override func viewDidLoad() {
super.viewDidLoad()

classViewController:UIViewController,
AVAudioPlayerDelegate {

I think it is a matter of hierarchy.
This is my first time using two SDKs, so I'm confused.

I would appreciate it if you could let me know if anyone knows.
Thank you for your cooperation.