def METHOD_NAME():
    # Set the values of the client ID, tenant ID, and client secret of the AAD application as
    # environment variables:
    #   AZURE_CLIENT_ID, AZURE_TENANT_ID, AZURE_CLIENT_SECRET, CONFIDENTIALLEDGER_ENDPOINT
    try:
        ledger_endpoint = os.environ["CONFIDENTIALLEDGER_ENDPOINT"]
    except KeyError:
        LOG.error(
            "Missing environment variable 'CONFIDENTIALLEDGER_ENDPOINT' - "
            "please set it before running the example"
        )
        sys.exit(1)
    # Under the current URI format, the ledger id is the first part of the ledger endpoint.
    # i.e. https://<ledger id>.confidential-ledger.azure.com
    ledger_id = ledger_endpoint.replace("https://", "").split(".")[0]
    identity_service_client = ConfidentialLedgerCertificateClient()  # type: ignore[call-arg]
    ledger_certificate = identity_service_client.get_ledger_identity(ledger_id)
    # The Confidential Ledger's TLS certificate must be written to a file to be used by the
    # ConfidentialLedgerClient. Here, we write it to a temporary file so that is is cleaned up
    # automatically when the program exits.
    with tempfile.TemporaryDirectory() as tempdir:
        ledger_cert_file = os.path.join(tempdir, f"{ledger_id}.pem")
        with open(ledger_cert_file, "w") as outfile:
            outfile.write(ledger_certificate["ledgerTlsCertificate"])
        print(
            f"Ledger certificate has been written to {ledger_cert_file}. "
            "It will be deleted when the script completes."
        )
        # Build a client through AAD
        ledger_client = ConfidentialLedgerClient(
            ledger_endpoint,
            credential=DefaultAzureCredential(),
            ledger_certificate_path=ledger_cert_file,
        )
        # Write a ledger entry.
        try:
            post_entry_result = ledger_client.create_ledger_entry(
                {"contents": "Hello world!"}
            )
            transaction_id = post_entry_result["transactionId"]
            print(
                f"Successfully sent a ledger entry to be written. It will become durable at "
                f"transaction id {transaction_id}"
            )
        except HttpResponseError as e:
            print("Request failed: {}".format(e.response.json()))  # type: ignore[union-attr]
            raise
        # For some scenarios, users may want to eventually ensure the written entry is durably
        # committed.
        try:
            print(
                f"Waiting for {transaction_id} to become durable. This may be skipped for when "
                "writing less important entries where client throughput is prioritized."
            )
            wait_poller = ledger_client.begin_wait_for_commit(transaction_id)  # type: ignore[attr-defined]
            wait_poller.wait()
            print(
                f"Ledger entry at transaction id {transaction_id} has been committed successfully"
            )
        except HttpResponseError as e:
            print("Request failed: {}".format(e.response.json()))  # type: ignore[union-attr]
            raise
        # Get the latest ledger entry.
        try:
            current_ledger_entry = ledger_client.get_current_ledger_entry()["contents"]
            print(f"The current ledger entry is {current_ledger_entry}")
        except HttpResponseError as e:
            print("Request failed: {}".format(e.response.json()))  # type: ignore[union-attr]
            raise
        # Users may wait for a durable commit when writing a ledger entry though this will reduce
        # client throughput.
        try:
            print(
                f"Writing another entry. This time, we'll have the client method wait for commit."
            )
            post_poller = ledger_client.begin_create_ledger_entry(  # type: ignore[attr-defined]
                {"contents": "Hello world again!"}
            )
            new_post_result = post_poller.result()
            print(
                "The new ledger entry has been committed successfully at transaction id "
                f'{new_post_result["transactionId"]}'
            )
        except HttpResponseError as e:
            print("Request failed: {}".format(e.response.json()))  # type: ignore[union-attr]
            raise
        # Get the latest ledger entry.
        try:
            current_ledger_entry = ledger_client.get_current_ledger_entry()["contents"]
            print(f"The current ledger entry is {current_ledger_entry}")
        except HttpResponseError as e:
            print("Request failed: {}".format(e.response.json()))  # type: ignore[union-attr]
            raise
        # Make a query for a prior ledger entry. The service may take some time to load the result,
        # so a poller is provided.
        try:
            get_entry_poller = ledger_client.begin_get_ledger_entry(transaction_id)  # type: ignore[attr-defined]
            get_entry_result = get_entry_poller.result()
            print(
                f'At transaction id {get_entry_result["entry"]["transactionId"]}, the ledger entry '
                f'contains \'{get_entry_result["entry"]["contents"]}\''
            )
        except HttpResponseError as e:
            print("Request failed: {}".format(e.response.json()))  # type: ignore[union-attr]
            raise