Dispatcher code example [StatelessWorker] attribute in wrong place? #12

In dispatcher example there is [StatelessWorker] attribute for IDispatcherGrain interface, but it should be in the DispatcherGrain class. In C# to my knowledge class don't inherit attributes from interfaces it uses.

[StatelessWorker]
public interface IDispatcherGrain : IGrain
{
    Task Send(Tuple<int, string>[] messages);
}