Unable to get GoogleSignInAccount class methods and attributes correctly

Question

I have managed to sign in my app to my google drive account. However, when trying to retrieve a drive service api, I was unable to retrieve my credentials and set them to get the drive. Upon further inspection, I realise that the GoogleSignInAccount class that I created looks different from the GoogleSignInAccount that is stated in the documentation found at https://developers.google.com/android/reference/com/google/android/gms/auth/api/signin/GoogleSignInAccount It doesn't have methods like getAcccount() or getemail(). Instead, the class instance in my app has weird attributes seen below:

As result my code results in a null exception invoked. googleAccount is my GoogleSignInAccount class instance. Running googleAccount.account and googleAccount.getAccount() both returns null.

Below is my full code if needed:

fun getDriveService() : Drive?{
        GoogleSignIn.getLastSignedInAccount(this)?.let { googleAccount ->
            val credential = GoogleAccountCredential.usingOAuth2(
                    this, listOf(DriveScopes.DRIVE_FILE)
            )
            println(googleAccount)
            credential.selectedAccount = googleAccount.account!!

            return Drive.Builder(
                    AndroidHttp.newCompatibleTransport(),
                    JacksonFactory.getDefaultInstance(),
                    credential
            )
                    .setApplicationName(getString(R.string.app_name))
                    .build()
        }
        return null
    }