public static IFluentApi <ArtistChart> WithPeriod(this IFluentApi <ArtistChart> api, ApiPeriod period)
 {
     api.WithParameter("period", period.ToString().ToLower());
     return(api);
 }
 public static IFluentApi<ArtistChart> WithPeriod(this IFluentApi<ArtistChart> api, ApiPeriod period)
 {
     api.WithParameter("period", period.ToString().ToLower());
     return api;
 }