def METHOD_NAME(region, subnet_id, expected_autoassign_ip_value, expected_availability_zone=""):
    """Check that the subnet has the given property."""
    subnet = boto3.resource("ec2", region_name=region).Subnet(subnet_id)
    assert_that(subnet.map_public_ip_on_launch).is_equal_to(expected_autoassign_ip_value)
    if expected_availability_zone:
        assert_that(subnet.availability_zone).is_equal_to(expected_availability_zone)