public static OptionsBuilder <TOptions> AddAdminSiteOptions <TOptions>(this OptionsBuilder <TOptions> optionsBuilder, Action <TOptions>?configureAdminOptions = null) where TOptions : SharePointSiteAuthorizationOptions => optionsBuilder.AddNestedNamedOptions( SharePointSiteAuthorizationOptions.AdminSiteOptionsName, configureAdminOptions, GetAdminUrlFromSiteUrl );