How to use the annif.exception.ConfigurationException function in annif

def test_maui_train_missing_endpoint(document_corpus, project):
    maui_type = annif.backend.get_backend("maui")
    maui = maui_type(
        backend_id='maui',
        config_params={
            'tagger': 'dummy',
            'language': 'en'},
        project=project)

    with pytest.raises(ConfigurationException):
        maui.train(document_corpus)

def _convert_param(self, param, val):
        pspec, _ = self.VW_PARAMS[param]
        if isinstance(pspec, list):
            if val in pspec:
                return val
            raise ConfigurationException(
                "{} is not a valid value for {} (allowed: {})".format(
                    val, param, ', '.join(pspec)), backend_id=self.backend_id)
        try:
            return pspec(val)
        except ValueError:
            raise ConfigurationException(
                "The {} value {} cannot be converted to {}".format(
                    param, val, pspec), backend_id=self.backend_id)

def backend(self):
        if self._backend is None:
            if 'backend' not in self.config:
                raise ConfigurationException(
                    "backend setting is missing", project_id=self.project_id)
            backend_id = self.config['backend']
            try:
                backend_class = annif.backend.get_backend(backend_id)
                self._backend = backend_class(
                    backend_id, config_params=self.config,
                    datadir=self.datadir)
            except ValueError:
                logger.warning(
                    "Could not create backend %s, "
                    "make sure you've installed optional dependencies",
                    backend_id)
        return self._backend

def _init_access(self):
        access = self.config.get('access', self.DEFAULT_ACCESS)
        try:
            self.access = getattr(Access, access)
        except AttributeError:
            raise ConfigurationException(
                "'{}' is not a valid access setting".format(access),
                project_id=self.project_id)

if not os.path.exists(projects_file):
        logger.warning(
            'Project configuration file "%s" is missing. Please provide one.' +
            ' You can set the path to the project configuration file using ' +
            'the ANNIF_PROJECTS environment variable or the command-line ' +
            'option "--projects".', projects_file)
        return {}

    config = configparser.ConfigParser()
    config.optionxform = lambda option: option
    with open(projects_file, encoding='utf-8') as projf:
        try:
            config.read_file(projf)
        except (configparser.DuplicateOptionError,
                configparser.DuplicateSectionError) as err:
            raise ConfigurationException(err)

    # create AnnifProject objects from the configuration file
    projects = collections.OrderedDict()
    for project_id in config.sections():
        projects[project_id] = AnnifProject(project_id,
                                            config[project_id],
                                            datadir)
        if init_projects:
            projects[project_id].initialize()
    return projects

def _convert_param(self, param, val):
        pspec, _ = self.VW_PARAMS[param]
        if isinstance(pspec, list):
            if val in pspec:
                return val
            raise ConfigurationException(
                "{} is not a valid value for {} (allowed: {})".format(
                    val, param, ', '.join(pspec)), backend_id=self.backend_id)
        try:
            return pspec(val)
        except ValueError:
            raise ConfigurationException(
                "The {} value {} cannot be converted to {}".format(
                    param, val, pspec), backend_id=self.backend_id)

def analyzer(self):
        if self._analyzer is None:
            if self.analyzer_spec:
                self._analyzer = annif.analyzer.get_analyzer(
                    self.analyzer_spec)
            else:
                raise ConfigurationException(
                    "analyzer setting is missing (and needed by the backend)",
                    project_id=self.project_id)
        return self._analyzer