```console $ 03_01_flag_bool_derive --help A simple to use, efficient, and full-featured Command Line Argument Parser Usage: 03_01_flag_bool_derive[EXE] [OPTIONS] Options: -v, --verbose -h, --help Print help -V, --version Print version $ 03_01_flag_bool_derive verbose: false $ 03_01_flag_bool_derive --verbose verbose: true $ 03_01_flag_bool_derive --verbose --verbose ? failed error: the argument '--verbose' was provided more than once, but cannot be used multiple times Usage: 03_01_flag_bool_derive[EXE] [OPTIONS] For more information try '--help' ```