TheAirline.Models.Airlines.Airline.AddInvoice C# (CSharp) Method

        public void AddInvoice(Invoice invoice, bool updateMoney = true)
        {
            Invoices.AddInvoice(invoice);

            if (updateMoney)
            {
                Money += invoice.Amount;
            }
        }

 //adds an invoice to an airline
 public static void AddAirlineInvoice(Airline airline, DateTime date, Invoice.InvoiceType type, double amount)
 {
     if (airline.IsHuman && GameObject.GetInstance().HumanAirline == airline)
     {
         GameObject.GetInstance().AddHumanMoney(amount);
         GameObject.GetInstance().HumanAirline.AddInvoice(new Invoice(date, type, amount), false);
     }
     else
         airline.AddInvoice(new Invoice(date, type, amount));
 }