def mark_done(path: Union[Path, str]) -> None:
    """Create ``.done`` empty file in the directory.

    Args:
        path: Path to directory.

    Raises:
        NotADirectoryError: If ``path`` does not point to a directory.

    """
    path = Path(path)
    if not path.is_dir():
        raise NotADirectoryError(f"Not a directory: '{path}'")
    mark = path / _MARK_DONE
    mark.touch(exist_ok=True)
Create ``.done`` empty file in the directory.

    Args:
        path: Path to directory.

    Raises:
        NotADirectoryError: If ``path`` does not point to a directory.

    
deeppavlov/core/data/utils.py