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);
}