def _sanitize_ipv4_mapping(ip_str):
    if not ip_str.lower().startswith('0000:0000:0000:0000:0000:ffff:'):
        # not an ipv4 mapping
        return ip_str

    hextets = ip_str.split(':')

    if '.' in hextets[-1]:
        # already sanitized
        return ip_str

    ipv4_address = "%d.%d.%d.%d" % (
        int(hextets[6][0:2], 16),
        int(hextets[6][2:4], 16),
        int(hextets[7][0:2], 16),
        int(hextets[7][2:4], 16),
    )

    result = ':'.join(hextets[0:6])
    result += ':' + ipv4_address

    return result
Override callLater to use the deterministic clock.
dataset/ETHPy150Open django/django/django/utils/ipv6.py/_sanitize_ipv4_mapping--crossover with--dataset/ETHPy150Open nlloyd/SubliminalCollaborator/libs/twisted/test/test_policies.py/TimeoutTester.callLater