internal void MetAJour(string idName, ValeurEchange ve)
        {
            //TODO : affiner les frais
            var json       = Site.client.GetOrderBook(idName);
            var jsonResult = (JsonObject)((JsonObject)json["result"])[idName];
            var jsonAsks   = (JsonArray)jsonResult["asks"];
            var jsonBids   = (JsonArray)jsonResult["bids"];

            PositionsAchatBase.Clear();
            PositionsVenteBase.Clear();
            foreach (JsonArray jsonAsk in jsonAsks)
            {
                PositionsAchatBase.Add(new PositionAchatBase(jsonAsk, monnaieDeBase, monnaieDeQuote));
            }
            foreach (JsonArray jsonBid in jsonBids)
            {
                PositionsVenteBase.Add(new PositionVenteBase(jsonBid, monnaieDeBase, monnaieDeQuote));
            }
        }
 internal List <Position> PositionsVente(Monnaie monnaieAVendre)
 {
     return(monnaieAVendre == monnaieDeBase?PositionsVenteBase.ConvertAll(x => (Position)x) : PositionsAchatBase.ConvertAll(x => (Position)x));
 }