private static void InvalidName()
 {
     try
     {
         var person = SmartPerson.Create(null, 30);
     }
     catch (ArgumentNullException ex)
     {
         WriteLine($"{ex.Message}");
     }
 }
 private static void InvalidAge()
 {
     try
     {
         var person = SmartPerson.Create("George", -1);
     }
     catch (ArgumentOutOfRangeException ex)
     {
         WriteLine($"{ex.Message}");
     }
 }
        private static void HappyPath()
        {
            var person = SmartPerson.Create("George", 30);

            WriteLine($"Valid person data so all goes well and we can print: {person}");
        }