def validate_args(options):
    """Validate the arguments to the various sub-commands.

    Parameters
    ----------
    options : :class:`argparse.Namespace`
        Parsed options.

    Returns
    -------
    :class:`bool`
        ``True`` if the arguments are valid.
    """
    nargs = {'attachment': {'add': 2, 'export': 2, 'list': 1, 'replace': 2},
             'wiki': {'export': 1, 'import': 1, 'list': 0, 'replace': 1}
             }
    return len(options.arguments) >= nargs[options.cmd_name][options.command]