def normalize_fmt_off(
    node: Node, mode: Mode, lines: Collection[tuple[int, int]]
) -> None:
    """Convert content between `# fmt: off`/`# fmt: on` into standalone comments."""
    try_again = True
    while try_again:
        try_again = convert_one_fmt_off_pair(node, mode, lines)
Convert content between `# fmt: off`/`# fmt: on` into standalone comments.
src/black/comments.py