private static void FindPerson(IPhoneBookRepository phoneBook, string firstName, string lastName)
        {
            var person = phoneBook.FindPerson(firstName, lastName);

            if (person != null)
            {
                Console.WriteLine("Result Person Found:");
                Console.WriteLine(String.Format("Name: {0} Phone: {1}, Address: {2}",
                                                person.FirstName + " " + person.LastName, person.PhoneNumber, person.Address));
            }
        }