@classmethod
def add_documentation(cls, argparse_obj):
    """set up argparse for command and all of its subcommands"""
    cmd_parser = super().add_documentation(argparse_obj)
    subcommands = cmd_parser.add_subparsers(title='subcommands', metavar=
        '<subcommand>', dest='subcommand')
    subcommands.required = True
    for sub_command in cls.sub_commands:
        sub_command.add_documentation(subcommands)
