A helper function useful to decode cp866-encoded filenames in tar archives.

decode_escaped_cp866.py

def decode_escaped_cp866(s):
    out = []
    for token in re.finditer(r"%([0-9A-F]{2})|(.)", s):
        if token.group(1) is not None:
            out.append(bytes([int(token.group(1), 16)]))
        elif token.group(2) is not None:
            out.append(token.group(2).encode('utf-8'))
    return b"".join(out).decode('cp866')
  
print(decode_escaped_cp866("%8C%A0%E0%A8%EF - %84%87"))
# Мария - ДЗ