code: func Join(list []string, delim string) string {
  	var buf bytes.Buffer
  	for i := 0; i < len(list)-1; i++ {
  		buf.WriteString(list[i] + delim)
  	}
  	buf.WriteString(list[len(list)-1])
  	return buf.String()
  }
docs: // Join joins the list of the string with the delim provided