How to get AX exchange rate

输入：原来的货币，转换的货币，时间
输出：AX系统的Exchange rate

public static ExchRate getExchRateFind(CurrencyCode _fromCurrency,
                                CurrencyCode _toCurrency,
                                TransDate _transDate = systemDateGet())
{
    ExchangeRateHelper      exchangeRateHelper;

    exchangeRateHelper = ExchangeRateHelper::newCurrencyToCurrency(_fromCurrency,_toCurrency);
    exchangeRateHelper.parmExchangeDate(_transDate);
    exchangeRateHelper.parmExchangeRateTypeRecId(Ledger::defaultExchangeRateType());

    return exchangeRateHelper.getExchangeRate1()/100;
}