ciphertext = [
    b'm\x99QH\xfc\x99\xcel\xfc>\x11\xf81\xda:\x15"6\xd3b\x07\x7f\xed\x87\xd5\xd4\xf0\xbb',
    b'x\x96^\r\xb5\x83\x86u\xeel\x0e\xf8,\xce:\x06 6\xd0b\nx\xfd\x87\xd9\xc9\xe8',
    b'm\x90O^\xfc\x80\xd3f\xe7>\x16\xf46\x89w\x05r8\xcb-\x04',
    b'`\x97O\r\xbd\x9f\xc3%\xe1q\x0e\xb15\xdbu\x0e5y\xca*\x1c7\xec\xc2\xd2\xcb',
    b"m\x90[Y\xfc\x80\xdf%\xeb\x7f\x03\xe2b\xc1{\x167y\xdf'\x16y\xa8\xc6\x97\xc2\xed\xa9p(",
    b'`\x9dN\r\xb5\x8b\x86m\xe0n\x1f\xb1*\xc8i@45\xd25\x1d7\xe9\xd0\xd6\xdf',
    b'p\x96\x1aL\xfc\x83\xcfb\xe7jZ\xfe0\x89s\x0er8\x9d&\x12n',
    b'p\x96\x1aL\xfc\x9b\xcfv\xe6q\x14\xb1-\xdb:\t<y\xd3-\x1dr',
    b'p\x8b\x1aD\xa8\xcd\xd2m\xeal\x1f\xf7-\xdb\x7f@&1\xd8b\x1fr\xfb\xd4\x97\xc1\xf0\xa2t',
    b'x\x94V\r\xa8\x85\xc7q\xafi\x1f\xb11\xcc\x7f@=+\x9d1\x16r\xe5',
    b'p\x8b\x1aO\xa9\x99\x86d\xafz\x08\xf4#\xc4:\x17;-\xd5+\x1d7\xe9\x87\xd3\xd4\xfa\xad|',
    b'p\xd8IY\xbd\x83\xc2%\xees\x13\xf5b\xddr\x05r+\xd2#\x01',
    b'v\x9e\x1aL\xfc\x9e\xd3w\xe9>\x0e\xfe0\xc4\x7f\x0e&<\xd9b\x00\x7f\xe7\xd5\xd2',
    b'x\x96^\r\x95\xcd\xcej\xe3zZ\xe6+\xddr\t<y\xd0;S\x7f\xe9\xc9\xd3',
    b"~\x8a[D\xb2\x9e\x86j\xe9>\x0e\xf9'\x89}\x0f>=\xd8,Sd\xe9\xc9\xd3",
    b'q\x97M\r\xba\x88\xd1%\xf6{\x0e\xb1*\xc6m@&1\xd8;St\xfa\xc2\xd2\xd6',
    b'm\x90HB\xa9\x8a\xce%\xe2gZ\xf7+\xc7}\x05 *\x9d6\x1c7\xfc\xcf\xd2\x86\xfb\xa9t5',
    b'n\x90SA\xb9\xcd\xcf%\xf8{\x1f\xe1b\xder\t><\x9d\x0bS`\xed\xc2\xc7',
    b'9\xd8_I\xbb\x8c\xd4%\xeer\x16\xf0,\x89j\x0f7y\x9dbS7\xa8\x87\x97\x86\xbf',
]

from string import ascii_lowercase

# set of allowed characters
letters = set(ascii_lowercase + ' ')

# reconstructed messages
plaintext = [''] * len(ciphertext)

# take all the codes at the same position
for messages in zip(*ciphertext):
    keys = set()
    
    # find viable keys
    for key in range(256):
        for m in messages:
            if chr(m ^ key) not in letters:
                break
        else:
            keys.add(key)

    key = keys.pop() if len(keys) == 1 else None

    # reconstruct plaintext
    for i, m in enumerate(messages):
        if key is not None:
            plaintext[i] += chr(m ^ key)
        else:
            plaintext[i] += '?'