How to use the voila.configuration.VoilaConfiguration function in voila

'Directory holding static assets (HTML, JS and CSS files).'
        )
    )
    aliases = {
        'port': 'Voila.port',
        'static': 'Voila.static_root',
        'strip_sources': 'VoilaConfiguration.strip_sources',
        'autoreload': 'Voila.autoreload',
        'template': 'VoilaConfiguration.template',
        'theme': 'VoilaConfiguration.theme',
        'base_url': 'Voila.base_url',
        'server_url': 'Voila.server_url',
        'enable_nbextensions': 'VoilaConfiguration.enable_nbextensions'
    }
    classes = [
        VoilaConfiguration,
        VoilaExecutePreprocessor,
        VoilaExporter,
        VoilaCSSPreprocessor
    ]
    connection_dir_root = Unicode(
        config=True,
        help=_(
            'Location of temporry connection files. Defaults '
            'to system `tempfile.gettempdir()` value.'
        )
    )
    connection_dir = Unicode()

    base_url = Unicode(
        '/',
        config=True,

arg = self.extra_args[0]
            # I am not sure why we need to check if self.notebook_path is set, can we get rid of this?
            if not self.notebook_path:
                if os.path.isdir(arg):
                    self.root_dir = arg
                elif os.path.isfile(arg):
                    self.notebook_path = arg
                else:
                    raise ValueError('argument is neither a file nor a directory: %r' % arg)
        elif len(self.extra_args) != 0:
            raise ValueError('provided more than 1 argument: %r' % self.extra_args)

        # then we load the config
        self.load_config_file('voila', path=self.config_file_paths)
        # common configuration options between the server extension and the application
        self.voila_configuration = VoilaConfiguration(parent=self)
        self.setup_template_dirs()
        signal.signal(signal.SIGTERM, self._handle_signal_stop)

def load_jupyter_server_extension(server_app):
    web_app = server_app.web_app

    nbconvert_template_paths = []
    static_paths = [STATIC_ROOT]
    template_paths = []

    # common configuration options between the server extension and the application
    voila_configuration = VoilaConfiguration(parent=server_app)
    collect_template_paths(
        nbconvert_template_paths,
        static_paths,
        template_paths,
        voila_configuration.template
    )

    jenv_opt = {"autoescape": True}
    env = Environment(loader=FileSystemLoader(template_paths), extensions=['jinja2.ext.i18n'], **jenv_opt)
    web_app.settings['voila_jinja2_env'] = env

    nbui = gettext.translation('nbui', localedir=os.path.join(ROOT, 'i18n'), fallback=True)
    env.install_gettext_translations(nbui, newstyle=False)

    host_pattern = '.*$'
    base_url = url_path_join(web_app.settings['base_url'])