I found this code from a tutorial:

```
Product bev1 = beverages.ElementAtOrDefault(10);
if (bev1 != null)
{
    Console.WriteLine("The price of {0} is {1}. Update to 20.0", 
                      bev1.ProductName, bev1.UnitPrice);
    bev1.UnitPrice = (decimal)20.0;
}
// submit the change to database
db.SubmitChanges();

```

How do we know if the update was successful?