code: func NewHexLiteral(s string) (HexLiteral, error) {
  	h, err := ParseHexStr(s)
  	if err != nil {
  		return HexLiteral{}, err
  	}
  	return HexLiteral(h), nil
  }
docs: // NewHexLiteral parses hexadecimal string as HexLiteral type.