public async Task <GetOffersReply> GetSellOffers(CurrencyOrAccountLocator locator, bool?availableOnly = null,
                                                         int?firstIndex = null, int?lastIndex = null, ulong?requireBlock = null, ulong?requireLastBlock = null)
        {
            var queryParameters = locator.QueryParameters;

            queryParameters.AddIfHasValue(Parameters.AvailableOnly, availableOnly);
            queryParameters.AddIfHasValue(Parameters.FirstIndex, firstIndex);
            queryParameters.AddIfHasValue(Parameters.LastIndex, lastIndex);
            queryParameters.AddIfHasValue(Parameters.RequireBlock, requireBlock);
            queryParameters.AddIfHasValue(Parameters.RequireLastBlock, requireLastBlock);
            return(await Get <GetOffersReply>("getSellOffers", queryParameters));
        }
        public async Task <ExchangesReply> GetExchanges(CurrencyOrAccountLocator locator, int?firstIndex = null,
                                                        int?lastIndex      = null, DateTime?timestamp     = null, bool?includeCurrencyInfo = null,
                                                        ulong?requireBlock = null, ulong?requireLastBlock = null)
        {
            var queryParameters = locator.QueryParameters;

            queryParameters.AddIfHasValue(Parameters.FirstIndex, firstIndex);
            queryParameters.AddIfHasValue(Parameters.LastIndex, lastIndex);
            queryParameters.AddIfHasValue(Parameters.IncludeCurrencyInfo, includeCurrencyInfo);
            queryParameters.AddIfHasValue(Parameters.Timestamp, timestamp);
            queryParameters.AddIfHasValue(Parameters.RequireBlock, requireBlock);
            queryParameters.AddIfHasValue(Parameters.RequireLastBlock, requireLastBlock);
            return(await Get <ExchangesReply>("getExchanges", queryParameters));
        }