public bool ValidOrderPrices(OrderBookEventArgs args, Instrument ins)
        {
            double expectedAmount;

            var bidOrder = ins.CreateBidOrder(this, out expectedAmount);
            var askOrder = ins.CreateAskOrder(this, out expectedAmount);

            GetPrice(args.OrderBook.Bids, args.OrderBook.Asks, expectedAmount, bidOrder, askOrder);

            if (bidOrder.Price == 0 && askOrder.Price == 0)
            {
                return(false);
            }

            //if (!ins.CheckConstraint(bidOrder.Price, askOrder.Price, CurrencyRate))
            //    return false;

            return(ins.ValidOrderPrices(this, bidOrder, askOrder));
        }