public async Task<double> CalculateRate(double value, string fromCurrency, string toCurrency)
        {
            // Get all rate values from API
            ExchangeRateData exchangeRates = await _exchangeRateApi.GetExchagneRates(toCurrency);

            // Get "FromCurrency" rate
            var rate = exchangeRates.Rates[fromCurrency];

            // Calculate and return
            return value * rate;
        }