Exchange rate details, specified as an object with the following parameters:
base_amountobject<money>Requiredcurrency_codestring<currency_code>RequiredvaluestringRequiredquote_amountobject<money>Requiredcurrency_codestring<currency_code>RequiredvaluestringRequiredexpiry_timestring<date_time>Optionalrate_refresh_timestring<date_time>Optionalupdate_timestring<date_time>Optional