How to use the voila.paths.collect_template_paths function in voila

def setup_template_dirs(self):
        if self.voila_configuration.template:
            collect_template_paths(
                self.nbconvert_template_paths,
                self.static_paths,
                self.template_paths,
                self.voila_configuration.template)
            # look for possible template-related config files
            template_conf_dir = [os.path.join(k, '..') for k in self.nbconvert_template_paths]
            conf_paths = [os.path.join(d, 'conf.json') for d in template_conf_dir]
            for p in conf_paths:
                # see if config file exists
                if os.path.exists(p):
                    # load the template-related config
                    with open(p) as json_file:
                        conf = json.load(json_file)
                    # update the overall config with it, preserving CLI config priority
                    if 'traitlet_configuration' in conf:
                        recursive_update(conf['traitlet_configuration'], self.voila_configuration.config.VoilaConfiguration)

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'])