How to use the flintrock.exceptions.Error function in Flintrock

def test_validate_invalid_download_source():
    with pytest.raises(Error):
        validate_download_source("https://www.apache.org/dyn/closer.lua?action=download&filename=hadoop/common/hadoop-2.8.3/hadoop-2.8.3.tar.gz")

    raises=Error,
)
def test_validate_valid_download_source():
    validate_download_source("https://www.apache.org/dyn/closer.lua?action=download&filename=hadoop/common/hadoop-2.8.5/hadoop-2.8.5.tar.gz")
    validate_download_source("https://www.apache.org/dyn/closer.lua?action=download&filename=spark/spark-2.4.4/spark-2.4.4-bin-hadoop2.7.tgz")

"""
    Get the block device map we should assign to instances launched from a given AMI.

    This is how we configure storage on the instance.
    """
    ec2 = boto3.resource(service_name='ec2', region_name=region)
    block_device_mappings = []

    try:
        image = list(
            ec2.images.filter(
                Filters=[
                    {'Name': 'image-id', 'Values': [ami]}
                ]))[0]
    except IndexError as e:
        raise Error(
            "Error: Could not find {ami} in region {region}.".format(
                ami=ami,
                region=region))

    if image.root_device_type == 'ebs':
        root_device = [
            device for device in image.block_device_mappings
            if device['DeviceName'] == image.root_device_name][0]
        if root_device['Ebs']['VolumeSize'] < min_root_ebs_size_gb:
            root_device['Ebs'].update({
                # Max root volume size for instance store-backed AMIs is 10 GiB.
                # See: http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/add-instance-store-volumes.html
                # Though, this code is probably incorrect for instance store-backed
                # instances anyway, since boto3 doesn't seem to let you set the size
                # of a root instance store volume.
                'VolumeSize': min_root_ebs_size_gb,

class UnsupportedProviderError(UsageError):
    def __init__(self, provider: str):
        super().__init__(
            "This provider is not supported: {p}".format(p=provider))
        self.provider = provider


class Error(Exception):
    pass


class ClusterNotFound(Error):
    pass


class ClusterAlreadyExists(Error):
    pass


class ClusterInvalidState(Error):
    def __init__(self, *, attempted_command: str, state: str):
        super().__init__(
            "Cluster is in state '{s}'. Cannot execute {c}.".format(
                c=attempted_command,
                s=state))
        self.attempted_command = attempted_command
        self.state = state


class SSHError(Error):
    def __init__(self, *, host: str, message: str):
        super().__init__(

def check_external_dependency(executable_name: str):
    if shutil.which(executable_name) is None:
        raise Error(
            "Error: Flintrock could not find '{executable}' on your PATH. "
            "Flintrock needs this executable to carry out the operation you "
            "requested. Please install it and try again."
            .format(
                executable=executable_name
            )

cluster = ec2.get_cluster(
            cluster_name=cluster_name,
            region=ec2_region,
            vpc_id=ec2_vpc_id)
        user = ec2_user
        identity_file = ec2_identity_file
        provider_options = {
            'min_root_ebs_size_gb': ec2_min_root_ebs_size_gb,
            'spot_price': ec2_spot_price,
            'tags': ec2_tags
        }
    else:
        raise UnsupportedProviderError(provider)

    if cluster.num_masters == 0:
        raise Error(
            "Cannot add slaves to cluster '{c}' since it does not "
            "appear to have a master."
            .format(
                c=cluster_name))

    cluster.load_manifest(
        user=user,
        identity_file=identity_file)
    cluster.add_slaves_check()

    if provider == 'ec2':
        cluster.add_slaves(
            user=user,
            identity_file=identity_file,
            num_slaves=num_slaves,
            assume_yes=assume_yes,

class ClusterAlreadyExists(Error):
    pass


class ClusterInvalidState(Error):
    def __init__(self, *, attempted_command: str, state: str):
        super().__init__(
            "Cluster is in state '{s}'. Cannot execute {c}.".format(
                c=attempted_command,
                s=state))
        self.attempted_command = attempted_command
        self.state = state


class SSHError(Error):
    def __init__(self, *, host: str, message: str):
        super().__init__(
            "[{h}] {m}".format(h=host, m=message))
        self.host = host
        self.message = message


class InterruptedEC2Operation(Error):
    def __init__(self, *, instances: list):
        super().__init__(
            "Operation aborted."
        )
        self.instances = instances

class UsageError(Exception):
    pass


class UnsupportedProviderError(UsageError):
    def __init__(self, provider: str):
        super().__init__(
            "This provider is not supported: {p}".format(p=provider))
        self.provider = provider


class Error(Exception):
    pass


class ClusterNotFound(Error):
    pass


class ClusterAlreadyExists(Error):
    pass


class ClusterInvalidState(Error):
    def __init__(self, *, attempted_command: str, state: str):
        super().__init__(
            "Cluster is in state '{s}'. Cannot execute {c}.".format(
                c=attempted_command,
                s=state))
        self.attempted_command = attempted_command
        self.state = state

if parsed_url.netloc == 'www.apache.org' and parsed_url.path == '/dyn/closer.lua':
        logger.warning(
            "Warning: "
            "Downloading {software} from an Apache mirror. Apache mirrors are "
            "often slow and unreliable, and typically only serve the most recent releases. "
            "We strongly recommend you specify a custom download source. "
            "For more background on this issue, please see: https://github.com/nchammas/flintrock/issues/238"
            .format(
                software=software,
            )
        )
        try:
            urllib.request.urlopen(url)
        except urllib.error.HTTPError as e:
            raise Error(
                "Error: Could not access {software} download. Maybe try a more recent release?\n"
                "  - Automatically redirected to: {url}\n"
                "  - HTTP error: {code}"
                .format(
                    software=software,
                    url=e.url,
                    code=e.code,
                )