Function format_field

python/python3/tornado/web.py:3415–3416

(s: Union[str, bytes])

        # - value (base64-encoded)
        # - signature (hex-encoded; no length prefix)
        def format_field(s: Union[str, bytes]) -> bytes:
            return utf8("%d:" % len(s)) + utf8(s)

        to_sign = b"|".join(
            [