def _unpack_ipv4(ip_str):
    if not ip_str.lower().startswith('0000:0000:0000:0000:0000:ffff:'):
        return None

    return ip_str.rsplit(':', 1)[1]
tests True function created.
dataset/ETHPy150Open django/django/django/utils/ipv6.py/_unpack_ipv4--crossover with--dataset/ETHPy150Open saltstack/salt/tests/unit/modules/boto_lambda_test.py/BotoLambdaFunctionTestCase.test_that_when_creating_a_function_from_zipfile_succeeds_the_create_function_method_returns_true