Fix iOS error in Google Mobile Ads SDK implementation

I need someone with experience developing apps using Flutter and Swift. Additionally, knowledge using the Google Mobile Ads SDK would be great but is not required as long as you can read documentation. I'm currently working on adding native ads to my Flutter app using a package, however, I'm encountering two errors that need to be fixed. The first error I'm receiving is: https://hastebin.com/opiqujabow.coffeescript. The second error is related to the Admob SDK, I think it's implemented incorrectly on the iOS side: https://hastebin.com/isidiqewes.apache. The package is https://pub.dev/packages/native_admob_flutter, and I think these are the relevant files: https://github.com/bdlukaa/native_admob_flutter/blob/master/ios/Classes/Native/NativeAdView.swift, https://github.com/bdlukaa/native_admob_flutter/blob/master/ios/Classes/Native/NativeAdViewFactory.swift. The package has an example folder which you can run to test it.