def base(ctx, verbose, config):
    """Puzzle: manage DNA variant resources."""
    # configure root logger to print to STDERR
    loglevel = LEVELS.get(min(verbose, 3))
    configure_stream(level=loglevel)
    ctx.obj = {}
    if config and os.path.exists(config):
        ctx.obj = yaml.load(open(config, 'r')) or {}
        ctx.obj['config_path'] = config
    # launch the command line interface
    logger.debug('Booting up command line interface')