How to use the acme.errors.ClientError function in acme

def _authzr_from_response(self, response, identifier,
                              uri=None, new_cert_uri=None):
        # pylint: disable=no-self-use
        if new_cert_uri is None:
            try:
                new_cert_uri = response.links['next']['url']
            except KeyError:
                raise errors.ClientError('"next" link missing')

        authzr = messages.AuthorizationResource(
            body=messages.Authorization.from_json(response.json()),
            uri=response.headers.get('Location', uri),
            new_cert_uri=new_cert_uri)
        if authzr.body.identifier != identifier:
            raise errors.UnexpectedUpdate(authzr)
        return authzr

if config.key_path is not None:  # revocation by cert key
        logger.debug("Revoking %s using cert key %s",
                     config.cert_path[0], config.key_path[0])
        crypto_util.verify_cert_matches_priv_key(config.cert_path[0], config.key_path[0])
        key = jose.JWK.load(config.key_path[1])
        acme = client.acme_from_config_key(config, key)
    else:  # revocation by account key
        logger.debug("Revoking %s using Account Key", config.cert_path[0])
        acc, _ = _determine_account(config)
        acme = client.acme_from_config_key(config, acc.key, acc.regr)
    cert = crypto_util.pyopenssl_load_certificate(config.cert_path[1])[0]
    logger.debug("Reason code for revocation: %s", config.reason)
    try:
        acme.revoke(jose.ComparableX509(cert), config.reason)
        _delete_if_appropriate(config)
    except acme_errors.ClientError as e:
        return str(e)

    display_ops.success_revocation(config.cert_path[0])
    return None

def _parse_regr_response(self, response, uri=None, new_authzr_uri=None,
                             terms_of_service=None):
        """
        Parse a registration response from the server.
        """
        links = _parse_header_links(response)
        if u'terms-of-service' in links:
            terms_of_service = links[u'terms-of-service'][u'url']
        if u'next' in links:
            new_authzr_uri = links[u'next'][u'url']
        if new_authzr_uri is None:
            raise errors.ClientError('"next" link missing')
        return (
            response.json()
            .addCallback(
                lambda body:
                messages.RegistrationResource(
                    body=messages.Registration.from_json(body),
                    uri=self._maybe_location(response, uri=uri),
                    new_authzr_uri=new_authzr_uri,
                    terms_of_service=terms_of_service))
            )

try:
                    raise messages.Error.from_json(jobj)
                except jose.DeserializationError as error:
                    # Couldn't deserialize JSON object
                    raise errors.ClientError((response, error))
            else:
                # response is not JSON object
                raise errors.ClientError(response)
        else:
            if jobj is not None and response_ct != cls.JSON_CONTENT_TYPE:
                logger.debug(
                    'Ignoring wrong Content-Type (%r) for JSON decodable '
                    'response', response_ct)

            if content_type == cls.JSON_CONTENT_TYPE and jobj is None:
                raise errors.ClientError(
                    'Unexpected response Content-Type: {0}'.format(response_ct))

        return response

def _regr_from_response(cls, response, uri=None, new_authzr_uri=None,
                            terms_of_service=None):
        if 'terms-of-service' in response.links:
            terms_of_service = response.links['terms-of-service']['url']
        if 'next' in response.links:
            new_authzr_uri = response.links['next']['url']

        if new_authzr_uri is None:
            raise errors.ClientError('"next" link missing')

        return messages.RegistrationResource(
            body=messages.Registration.from_json(response.json()),
            uri=response.headers.get('Location', uri),
            new_authzr_uri=new_authzr_uri,
            terms_of_service=terms_of_service)

jobj = None

        if not response.ok:
            if jobj is not None:
                if response_ct != cls.JSON_ERROR_CONTENT_TYPE:
                    logger.debug(
                        'Ignoring wrong Content-Type (%r) for JSON Error',
                        response_ct)
                try:
                    raise messages.Error.from_json(jobj)
                except jose.DeserializationError as error:
                    # Couldn't deserialize JSON object
                    raise errors.ClientError((response, error))
            else:
                # response is not JSON object
                raise errors.ClientError(response)
        else:
            if jobj is not None and response_ct != cls.JSON_CONTENT_TYPE:
                logger.debug(
                    'Ignoring wrong Content-Type (%r) for JSON decodable '
                    'response', response_ct)

            if content_type == cls.JSON_CONTENT_TYPE and jobj is None:
                raise errors.ClientError(
                    'Unexpected response Content-Type: {0}'.format(response_ct))

        return response

try:
                    raise messages.Error.from_json(jobj)
                except jose.DeserializationError as error:
                    # Couldn't deserialize JSON object
                    raise errors.ClientError((response, error))
            else:
                # response is not JSON object
                raise errors.ClientError(response)
        else:
            if jobj is not None and response_ct != cls.JSON_CONTENT_TYPE:
                logger.debug(
                    'Ignoring wrong Content-Type (%r) for JSON decodable '
                    'response', response_ct)

            if content_type == cls.JSON_CONTENT_TYPE and jobj is None:
                raise errors.ClientError(
                    'Unexpected response Content-Type: {0}'.format(response_ct))

        return response

def check_cert(self, certr):
        """Check for new cert.

        :param certr: Certificate Resource
        :type certr: `.CertificateResource`

        :returns: Updated Certificate Resource.
        :rtype: `.CertificateResource`

        """
        # TODO: acme-spec 5.1 table action should be renamed to
        # "refresh cert", and this method integrated with self.refresh
        response, cert = self._get_cert(certr.uri)
        if 'Location' not in response.headers:
            raise errors.ClientError('Location header missing')
        if response.headers['Location'] != certr.uri:
            raise errors.UnexpectedUpdate(response.text)
        return certr.update(body=cert)

if config.key_path is not None:  # revocation by cert key
        logger.debug("Revoking %s using cert key %s",
                     config.cert_path[0], config.key_path[0])
        crypto_util.verify_cert_matches_priv_key(config.cert_path[0], config.key_path[0])
        key = jose.JWK.load(config.key_path[1])
        acme = client.acme_from_config_key(config, key)
    else:  # revocation by account key
        logger.debug("Revoking %s using Account Key", config.cert_path[0])
        acc, _ = _determine_account(config)
        acme = client.acme_from_config_key(config, acc.key, acc.regr)
    cert = crypto_util.pyopenssl_load_certificate(config.cert_path[1])[0]
    logger.debug("Reason code for revocation: %s", config.reason)
    try:
        acme.revoke(jose.ComparableX509(cert), config.reason)
        _delete_if_appropriate(config)
    except acme_errors.ClientError as e:
        return str(e)

    display_ops.success_revocation(config.cert_path[0])
    return None