```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 (see a summary with '-h') -V, --version Print version $ 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 (see more with '--help') -V, --version Print version $ 04_01_enum_derive fast Hare $ 04_01_enum_derive slow Tortoise $ 04_01_enum_derive medium ? failed error: invalid value 'medium' for '' [possible values: fast, slow] For more information, try '--help'. ```