def METHOD_NAME():
    client = boto3.client("ec2", region_name="us-east-1")
    with pytest.raises(ClientError) as ex:
        client.describe_regions(DryRun=True)
    assert ex.value.response["ResponseMetadata"]["HTTPStatusCode"] == 412
    assert ex.value.response["Error"]["Code"] == "DryRunOperation"
    assert (
        ex.value.response["Error"]["Message"]
        == "An error occurred (DryRunOperation) when calling the DescribeRegions operation: Request would have succeeded, but DryRun flag is set"
    )