public static void Main(string[] args)
        {
            Cashier c1 = new Cashier()
            {
                id   = 1,
                name = "Bob"
            };

            Cashier c2 = new Cashier()
            {
                id   = 2,
                name = "Jack"
            };

            Console.WriteLine(String.Format("Employee name: {0}, Employee id: {1}", c1.name, c1.id));
            //Console.WriteLine("Employee name: {0}, Employee id: {1}", c1.name, c1.id);

            StoreSale sale1 = StoreSale.NewSale(c1);

            Console.WriteLine(String.Format("SaleNumber: {0}, Cashier: {1}", sale1.CreatedAt.ToString("dd/MM/yyyy hh:mm:ss.fff"), sale1.CurrentCashier.name));

            StoreSale sale2 = StoreSale.NewSale(c2);

            Console.WriteLine(String.Format("SaleNumber: {0}, Cashier: {1}", sale2.CreatedAt.ToString("dd/MM/yyyy hh:mm:ss.fff"), sale2.CurrentCashier.name));
            Console.ReadLine();
        }
        public static StoreSale NewSale(Cashier NewCashier)
        {
            StoreSale sale = new StoreSale();

            sale.CreatedAt      = DateTime.Now;
            sale.CurrentCashier = NewCashier;

            //Console.WriteLine("CreatedAt: {0}, CurrentCashier: {1}", CreatedAt, CurrentCashier.name);
            //Console.ReadLine();

            return(sale);
        }