func (fu fileUtil) ReadByLines(filePath string, handler func(line string) error) error {
	var f *os.File
	var err error
	if f, err = os.Open(filePath); err == nil {
		defer f.Close()
		var line string
		scanner := bufio.NewScanner(f)
		for scanner.Scan() {
			line = scanner.Text()
			err = handler(line)
			if err != nil {
				return err
			}
		}
	}
	return err

}