I'm trying to use an external openid backoffice authentication provider following the steps on https://docs.umbraco.com/umbraco-cms/reference/security/external-login-providers/

In the article there is an example of a custom backoffice authentication provider, but It isn't compiling for me. Visual studio is telling me "AddProvider" is not a method. I do have access to an "AddOauth" method but I want to use OpenId Connect, not just OAuth2.

I am using Umbraco 12.3.3. Do you think I am missing some dependency, am I on the wrong version, or is there a problem with the example code?

public static class ProviderBackofficeAuthenticationExtensions {

public static IUmbracoBuilder AddProviderBackofficeAuthentication(this IUmbracoBuilder builder)
{
    // [OPTIONAL]
    // Register ProviderBackOfficeExternalLoginProviderOptions here rather than require it in startup
    builder.Services.ConfigureOptions<ProviderBackOfficeExternalLoginProviderOptions>();
    builder.AddBackOfficeExternalLogins(logins =>
    {
        logins.AddBackOfficeLogin(
            backOfficeAuthenticationBuilder =>
            {
                backOfficeAuthenticationBuilder.AddProvider(  // <-- Right HERE
                    backOfficeAuthenticationBuilder.SchemeForBackOffice(ProviderBackOfficeExternalLoginProviderOptions.SchemeName),
                    options =>
                    {