def add_subparser(subparsers):
    list_parser = subparsers.add_parser(
        'list',
        help="Display a list of PaaSTA services",
        description=(
            "'paasta list' inspects the soa-configs directory and lists all of the "
            "PaaSTA services that are declared."
        ),
    )
    list_parser.add_argument(
        '-a', '--all',
        action='store_true',
        help='Display all services, even if not on PaaSTA.')
    list_parser.add_argument(
        '-i', '--print-instances',
        action='store_true',
        help='Display all service%sinstance values, which only PaaSTA services have.' % SPACER)
    list_parser.set_defaults(command=paasta_list)
dataset/ETHPy150Open Yelp/paasta/paasta_tools/cli/cmds/list.py/add_subparser/original