How to use the refgenie.exceptions.MissingGenomeConfigError function in refgenie

parser = logmuse.add_logging_options(build_argparser())
    args, remaining_args = parser.parse_known_args()
    global _LOGGER
    _LOGGER = logmuse.logger_via_cli(args, make_root=True)
    _LOGGER.debug("refgenie {}".format(__version__))
    _LOGGER.debug("Args: {}".format(args))

    if not args.command:
        parser.print_help()
        _LOGGER.error("No command given")
        sys.exit(1)

    gencfg = refgenconf.select_genome_config(filename=args.genome_config, check_exist=not args.command == INIT_CMD,
                                             on_missing=lambda fp: fp, strict_env=True)
    if gencfg is None:
        raise MissingGenomeConfigError(args.genome_config)
    _LOGGER.debug("Determined genome config: {}".format(gencfg))

    # From user input we want to construct a list of asset dicts, where each
    # asset has a genome name, asset name, and tag

    if "asset_registry_paths" in args and args.asset_registry_paths:
        _LOGGER.debug("Found registry_path: {}".format(args.asset_registry_paths))
        asset_list = [parse_registry_path(x) for x in args.asset_registry_paths]

        for a in asset_list:
            # every asset must have a genome, either provided via registry path
            # or the args.genome arg.
            if not a["genome"]:
                if args.genome:
                    a["genome"] = args.genome
                else:

def __init__(self, conf_file=None):
        """
        Create the error message, using optionally an attempt filepath.

        :param str conf_file: path attempted to be used as genome config file
        """
        msg = "You must provide a config file either as an argument or via an environment variable: {}"\
            .format(", ".join(CFG_ENV_VARS))
        if conf_file:
            msg = "Not a file {} -- {}.".format(conf_file, msg)
        super(MissingGenomeConfigError, self).__init__(msg)

def main():
    """ main workflow """
    parser = build_argparser()
    args, remaining_args = parser.parse_known_args()
    cfg = select_config(args.config, refgenconf.CFG_ENV_VARS, check_exist=True, strict_env=True)
    if not cfg:
        raise MissingGenomeConfigError(args.config)
    rgc = refgenconf.RefGenConf(filepath=cfg, writable=True)
    pths = [args.path, mkabs(args.path, rgc.genome_folder)]
    if not untar_or_copy(pths[0], os.path.join(rgc.genome_folder, args.genome)) \
            and not untar_or_copy(pths[1], os.path.join(rgc.genome_folder, args.genome)):
        rgc.unlock()
        raise OSError("Path '{}' does not exist. Tried: {}".format(args.path, " and ".join(pths)))
    path_components = [rgc.genome_folder] + [args.genome] + ["*"] * 3 + ["Sequence"]
    assets_paths = glob(os.path.join(*path_components))
    assert len(assets_paths) > 0, OSError("Your iGenomes directory is corrupted, more than one directory matched by {}."
                                          "\nMatched dirs: {}".format(os.path.join(*path_components),
                                                                      ", ".join(assets_paths)))
    assets_path = assets_paths[0]
    asset_names = [d for d in os.listdir(assets_path) if os.path.isdir(assets_path)]
    processed = []
    for a in asset_names:
        asset_dict = {"genome": args.genome, "asset": a, "tag": None, "seek_key": None}