import random


def get_random_mac(base_mac):
    """Get a random MAC address string of the specified base format.

    Any part that is '00' will be randomized

    :param base_mac: Base MAC address represented by an array of 6 strings/int
    :returns: The MAC address string.
    """

    return ':'.join(
        "{:02x}".format(random.randint(0x00, 0xff))if p == '00' else p
        for p in base_mac
    )