public IEnumerable <ExchangeRate> GetExchangeRates(IEnumerable <Currency> currencies)
        {
            var      requiredCodesCur = currencies.Select(c => c.Code).ToList();
            var      relevantExcRates = new List <ExchangeRate>();
            Currency comparedCurency  = new Currency(targetCurrency);
            var      ratesRequest     = new RateRequestModel()
            {
                Date       = DateTime.Today.ToString(AcceptedDateFormat),
                RequestUrl = ExchangeSourceUrl
            };
            ExchangeRateResponse ratesResponse = ratesReqClient.GetRatesData(ratesRequest);

            if (ratesResponse != null && ratesResponse.Table.RatesRows.Length > 0)
            {
                foreach (var rate in ratesResponse.Table.RatesRows)
                {
                    if (requiredCodesCur.Contains(rate.Code))
                    {
                        relevantExcRates.Add(new ExchangeRate(new Currency(rate.Code), comparedCurency, (decimal)Convert.ToDecimal(rate.Rate) / Convert.ToInt32(rate.Amount)));
                    }
                    else
                    {
                        continue;
                    }
                }
            }


            return(relevantExcRates);
        }
        public ExchangeRateResponse GetRatesData(RateRequestModel req, CancellationToken cancelToken = default(CancellationToken))
        {
            string fullUrl = req.RequestUrl + req.Date;
            ExchangeRateResponse ratesResponse = null;

            try
            {
                using (client = new HttpClient())
                {
                    var response = client.GetAsync(fullUrl).Result;
                    if (response.StatusCode == HttpStatusCode.OK)
                    {
                        var           responseXML = response.Content.ReadAsStringAsync().Result;
                        var           bytes       = Encoding.UTF8.GetBytes(responseXML);
                        var           stream      = new MemoryStream(bytes);
                        XmlSerializer _serializer = new XmlSerializer(typeof(ExchangeRateResponse));
                        using (XmlReader reader = XmlReader.Create(stream))
                        {
                            ratesResponse = (ExchangeRateResponse)_serializer.Deserialize(reader);
                            reader.Close();
                        }
                        return(ratesResponse);
                    }
                }
            }
            catch (Exception e)
            {
                Console.Error.WriteLine("Exception: " + e.Message);
            }
            return(null);
        }