public void AddBillItem(BillItem billItem) { BillItems.Add(billItem); }
public void AddBillItem(string description, decimal unitPrice) { BillItems.Add(new BillItem(description, unitPrice)); }
public void AddBillItem(BillItem billItem) { BillItems.Add(billItem); }
public void AddBillItem(string description, decimal unitPrice) { BillItems.Add(new BillItem(description, unitPrice)); }