How to use the acme.errors.UnexpectedUpdate 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

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

def _check_challenge(cls, challenge, challenge_body):
        """
        Check that the challenge resource we got is the one we expected.
        """
        if challenge.uri != challenge_body.uri:
            raise errors.UnexpectedUpdate(challenge.uri)
        return challenge

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

"""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)

"""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)

def update_registration(self, regr, update=None):
        """Update registration.

        :param messages.RegistrationResource regr: Registration Resource.
        :param messages.Registration update: Updated body of the
            resource. If not provided, body will be taken from `regr`.

        :returns: Updated Registration Resource.
        :rtype: `.RegistrationResource`

        """
        update = regr.body if update is None else update
        updated_regr = self._send_recv_regr(
            regr, body=messages.UpdateRegistration(**dict(update)))
        if updated_regr != regr:
            raise errors.UnexpectedUpdate(regr)
        return updated_regr