def common_currency_code(self, currency):
    if (not self.substituteCommonCurrencyCodes):
        return currency
    return self.safe_string(self.commonCurrencies, currency, currency)
def common_currency_code(self, currency):
    if (not self.substituteCommonCurrencyCodes):
        return currency
    return self.safe_string(self.commonCurrencies, currency, currency)