A pure python `hexdump -C` mimic

hexdump.py

import string
from itertools import zip_longest
from typing import Iterable, Optional

def hexdump(bs: bytes) -> str:
    """A pure python `hexdump -C` mimic

    >>> print(hexdump(string.printable.encode('ascii')))
    000000000 30 31 32 33 34 35 36 37 38 39 61 62 63 64 65 66 |0123456789abcdef|
    000000010 67 68 69 6a 6b 6c 6d 6e 6f 70 71 72 73 74 75 76 |ghijklmnopqrstuv|
    000000020 77 78 79 7a 41 42 43 44 45 46 47 48 49 4a 4b 4c |wxyzABCDEFGHIJKL|
    000000030 4d 4e 4f 50 51 52 53 54 55 56 57 58 59 5a 21 22 |MNOPQRSTUVWXYZ!"|
    000000040 23 24 25 26 27 28 29 2a 2b 2c 2d 2e 2f 3a 3b 3c |#$%&'()*+,-./:;<|
    000000050 3d 3e 3f 40 5b 5c 5d 5e 5f 60 7b 7c 7d 7e 20 09 |=>?@[\]^_`{|}~..|
    000000060 0a 0d 0b 0c                                     |....            |
    """
    ascii = (string.digits + string.ascii_letters + string.punctuation).encode('ascii')

    def _int_to_ascii(i: int, default: str = '.') -> str:
        return chr(i) if i in ascii else default

    def _dump_line(idx: int, chunk: Iterable[Optional[bytes]]) -> str:
        idxpart = f'{idx:08x}0'
        hexpart = ' '.join('  ' if i is None else f'{i:02x}' for i in chunk)
        asciipart = ''.join(' ' if i is None else _int_to_ascii(i) for i in chunk)
        return f'{idxpart} {hexpart} |{asciipart}|'

    return '\n'.join(
        _dump_line(i, chunk)
        for i, chunk in enumerate(zip_longest(*([iter(bs)] * 16)))
    )