def METHOD_NAME(self, fan_num, node_num):
    if fan_num < self.FAN_NUM_1_IDX or fan_num > self.FAN_NUM_ON_MAIN_BROAD:
        logging.debug('GET. Parameter error. fan_num:%d', fan_num)
        return None
    if node_num < self.FAN_NODE_FAULT_IDX_OF_MAP or node_num > self.FAN_NODE_NUM_OF_MAP:
        logging.debug('GET. Parameter error. node_num:%d', node_num)
        return None
    device_path = self.get_fan_device_path(fan_num, node_num)
    try:
        val_file = open(device_path, 'r')
    except IOError as e:
        logging.error('GET. unable to open file: %s', str(e))
        return None
    content = val_file.readline().rstrip()
    if content == '':
        logging.debug('GET. content is NULL. device_path:%s', device_path)
        return None
    try:
        val_file.close()
    except Exception:
        logging.debug(
            'GET. unable to close file. device_path:%s',
            device_path)
        return None
    return int(content)