public static void Main()
        {
            Employee employee1 = new Employee();
            Employee employee2;
            employee2 = new Employee();

            employee1.FirstName = "Inigo";
            employee1.LastName = "Montoya";
            employee1.Salary = "Too Little";
            IncreaseSalary(employee1);
            Console.WriteLine(
                $"{ employee1.GetName() }: { employee1.Salary }");

        }
 static void IncreaseSalary(Employee employee)
 {
     employee.Salary = "Enough to survive on";
 }