```console $ 04_01_enum_derive --help A simple to use, efficient, and full-featured Command Line Argument Parser Usage: 04_01_enum_derive[EXE] Arguments: What mode to run the program in Possible values: - fast: Run swiftly - slow: Crawl slowly but steadily Options: -h, --help Print help information (use `-h` for a summary) -V, --version Print version information $ 04_01_enum_derive -h A simple to use, efficient, and full-featured Command Line Argument Parser Usage: 04_01_enum_derive[EXE] Arguments: What mode to run the program in [possible values: fast, slow] Options: -h, --help Print help information (use `--help` for more detail) -V, --version Print version information $ 04_01_enum_derive fast Hare $ 04_01_enum_derive slow Tortoise $ 04_01_enum_derive medium ? failed error: "medium" isn't a valid value for '' [possible values: fast, slow] For more information try '--help' ```