import binascii


def bin2macaddress(data):
    """Convert a byte-string to a MAC address."""

    mac = binascii.b2a_hex(data)
    chunks = list()
    for i in range(len(mac)):
        if i % 2 == 0:
            chunks.append(mac[i : i + 2])

    result = b":".join(chunks)
    return result.decode()