func requestForBannerView(viewController: UIViewController?) -> UIView {
        guard let bannerView = GADBannerManager().createRequestForBannerView(viewController: viewController) else {
            return UIView()  // Return an empty view if the banner creation fails
        }
        return bannerView  // Return the bannerView directly as UIView
    }
    func createRequestForBannerView(viewController: UIViewController?) -> GADBannerView? {
        bannerView = GADBannerView(adSize: GADAdSizeBanner)
        bannerView?.adUnitID = getBannerAdUnitID()
        bannerView?.rootViewController = viewController
        bannerView?.delegate = self
        bannerView?.load(GADRequest())
        return bannerView
    }

• bannerView: Banner view where the ad will present and this object will user to add on super view.
• viewController: where the banner will be visible.

extension GADBannerManager: GADBannerViewDelegate {
    func adViewDidReceiveAd(_ bannerView: GADBannerView) {
        // Add banner to view and add constraints as above.
        print("Banner loaded successfully")
    }
    func bannerView(_ bannerView: GADBannerView, didFailToReceiveAdWithError error: Error) {
        print("Fail to receive ads",error)
        print(error)
    }
    /// Tells the delegate that a full-screen view will be presented in response
    /// to the user clicking on an ad.
    func bannerViewWillPresentScreen(_ bannerView: GADBannerView) {
        print("adViewWillPresentScreen")
    }
    /// Tells the delegate that the full-screen view will be dismissed.
    func bannerViewWillDismissScreen(_ bannerView: GADBannerView) {
        print("adViewWillDismissScreen")
    }
    /// Tells the delegate that the full-screen view has been dismissed.
    func bannerViewDidDismissScreen(_ bannerView: GADBannerView) {
        print("adViewDidDismissScreen")
    }
    /// Tells the delegate that a user click will open another app (such as
    /// the App Store), backgrounding the current app.
    func adViewWillLeaveApplication(_ bannerView: GADBannerView) {
        print("adViewWillLeaveApplication")
    }
}

• Banner view delegate view callbacks methods which will handle request response