public void Remove(Product product)
 {
     dictionary.Remove (product.Id);
 }
 public void Remove(Product product)
 {
     using (var session = GetSession ()) {
         session.Delete (product);
     }
 }
 public void Add(Product product)
 {
     dictionary.Add (product.Id, product);
 }
 public void Add(Product product)
 {
     using (var session = GetSession ()) {
         session.Save (product);
     }
 }