public static IUserService CreateUserService(Container parentContainer, Container configurationContainer)
{
var container = new Container();
IUserSource userSource = SourceProvider.GetUserSource(parentContainer);
var config = configurationContainer.GetInstance <INewsFeedConfiguration>();
ICacheService <string, IEnumerable <User> > cache =
CacheServiceBuilder <string, IEnumerable <User> > .CreateService(config.UserInvalidationTime, CacheItemPriority.NotRemovable);
container.RegisterInstance(userSource);
container.Register <IUserService, UserService>();
container.RegisterInstance(cache);
container.Verify();
return(container.GetInstance <IUserService>());
}