def METHOD_NAME(self, index):
    if (index == 1):
        attr_file = 'in129_input'
    elif (index == 2):
        attr_file = 'in124_input'
    else:
        logging.error("Invalid PSU number:", index)
        return 0.0
    voltage = self.get_attr_value(self.HWMON_PATH + attr_file)
    voltage = voltage.rstrip()
    if (voltage != 'ERR'):
        voltage, dummy = voltage.split('.', 1)
    else:
        return 0.0
    return float(voltage)/1000