code: func ValidateKVList(kind string, list []string, sep rune) error {
  	for _, item := range list {
  		if !strings.ContainsRune(item, sep) {
  			return fmt.Errorf("bad %s, not a 'key%svalue' pair: %q", kind, string(sep), item)
  		}
  	}
  	return nil
  }
docs: // ValidateKVList makes sure each string in the list is valid key-value pair.