Post #2445756

If you want to more deeply customize the message shown to the user, you can raise an argparse.ArgumentTypeError instead of a ValueError: def date(string): try: return dt.‍date.fromisoformat(string) except ValueError: message = "invalid YYYY-MM-DD date: {string!r}" raise argparse.ArgumentTypeError(message) from None If we had raised a ValueError, the printed message will be prefixed with "argument date: ". Not so bad, but sometimes unwanted. 🧵 (3/3)