lang: str = typer.Argument(
        None, callback=lang_callback, autocompletion=complete_existing_lang
    ),
) -> None:
    """
    Serve with livereload a docs site for a specific language.

    This only shows the actual translated files, not the placeholders created with
    build-all.

    Takes an optional LANG argument with the name of the language to serve, by default
    en.
    """

    Read more about it in the
    [FastAPI docs for Configure Swagger UI](https://fastapi.tiangolo.com/how-to/configure-swagger-ui/)
    and the [FastAPI docs for Custom Docs UI Static Assets (Self-Hosting)](https://fastapi.tiangolo.com/how-to/custom-docs-ui-assets/).
    """
    current_swagger_ui_parameters = swagger_ui_default_parameters.copy()
    if swagger_ui_parameters: