def METHOD_NAME(metrics_files: Iterable[str]) -> Dict[str, Dict[datetime, str]]:
    """return {"node nickname": {datetime: path, ...}, ...}}"""
    filesByNick = {}
    tf_inventory_path = None
    for path in metrics_files:
        fname = os.path.basename(path)
        if fname == 'terraform-inventory.host':
            tf_inventory_path = path
            continue
        m = metrics_fname_re.match(fname)
        if not m:
            continue
        nick = m.group(1)
        timestamp = m.group(2)
        timestamp = datetime.strptime(timestamp, '%Y%m%d_%H%M%S')
        dapp(filesByNick, nick, timestamp, path)
    return tf_inventory_path, filesByNick