protected override void Save(string id, IDictionary<string, object> items)
        {
            Guard.NotNullOrEmpty(() => id, id);
            Guard.NotNull(() => items, items);

            var session = new Models.Session
            {
                Id = Guid.Parse(id),
                Items = items
            };

            using (var work = documentStore.OpenSession())
            {
                work.Store(session);
                work.SaveChanges();
            }
        }
        protected override void Save(string id, IDictionary <string, object> items)
        {
            Guard.NotNullOrEmpty(() => id, id);
            Guard.NotNull(() => items, items);

            var session = new Models.Session
            {
                Id    = Guid.Parse(id),
                Items = items
            };

            using (var work = documentStore.OpenSession())
            {
                work.Store(session);
                work.SaveChanges();
            }
        }