validation.go
func CheckPassword(pass string, min, max int) error {
	if len(pass) < min || len(pass) > max {
		return e.New(ErrInvalidPassLength)
	}
	for _, r := range pass {
		if !unicode.IsGraphic(r) {
			return e.New(ErrInvalidPassChar)
		}
	}
	return nil
}
func CheckPassword(pass string, min, max int) error {
	if len(pass) < min || len(pass) > max {
		return e.New(ErrInvalidPassLength)
	}
	for _, r := range pass {
		if !unicode.IsGraphic(r) {
			return e.New(ErrInvalidPassChar)
		}
	}
	return nil
}
// Check the user password. Graphics character are allowed. See unicode.IsGraphic.