How to hide optional params in `usage_lines`

[zhouzq-thu]

usage:
    ./a.out -o <PATH> -z <INT>... [-n <NAME>] [-s <SRC>] [-t <FLT>] [-b <FLT>] [-l <FLT>] [-r <FLT>]
            [--verbose] [-h]

    ./a.out -o <PATH> --zrange <MIN> <MAX> [<STEP=1>] [-n <NAME>] [-s <SRC>] [-t <FLT>] [-b <FLT>]
            [-l <FLT>] [-r <FLT>] [--verbose] [-h]

How to hide optional params in usage_lines:

usage:
    ./a.out -o <PATH> -z <INT>... 
    ./a.out -o <PATH> --zrange <MIN> <MAX>