static void Main(string[] args)
        {
            var customer = new Customer()
            {
                Address = new Address()
            };
            var validator = new CustomerValidator();
            var results   = validator.Validate(customer);

            if (!results.IsValid)
            {
                foreach (var error in results.Errors)
                {
                    Console.WriteLine(error.ErrorMessage);
                }
            }
        }