public HistoMinuteList GetPriceHistory(string exchange, string fromSymbol, string toSymbol, long timestamp) { var key = $"{exchange}_{fromSymbol}_{toSymbol}"; var pricingList = _cryptoCompareDataService.GetCoinHistoryForExchange(exchange, fromSymbol, toSymbol, timestamp); _coinPricing[key] = _builderFactory.CreateCollection <HistoMinuteItem, PricingItem>(pricingList.Data).Build().ToList(); return(pricingList); }