How to writeFile???

[Hodoio]

func WriteByString(path string, data string) bool {
	fileFlock := flock.New(path)
	if err := fileFlock.RLock(); err != nil {
		return false
	}
	file, err := os.Open(path)
	if err != nil {
		return false
	}
	if _, err := io.WriteString(file, data); err != nil {
		fmt.Println(err.Error())
		return false
	}
	return true
}

error:

write ./set.txt: Access is denied.