Takes an optional LANG argument with the name of the language to serve, by default
    en.
    """
    # Enable line numbers during local development to make it easier to highlight
    if lang is None:
        lang = "en"
    lang_path: Path = docs_path / lang
    # Enable line numbers during local development to make it easier to highlight
    args = ["mkdocs", "serve", "--dev-addr", "127.0.0.1:8008"]
    if dirty:

### Internal

* 🔨 Enable linenums in MkDocs Material during local live development to simplify highlighting code. PR [#9769](https://github.com/tiangolo/fastapi/pull/9769) by [@tiangolo](https://github.com/tiangolo).