def _get_http_headers(
    *,
    user_agent: str | None = None,
    referer: str | None = None,
    accept_language: str | None = None,
) -> dict[str, str]:
    """
    Update the default requests HTTP headers with OSMnx information.

    Parameters
    ----------
    user_agent
        The user agent. If None, use `settings.http_user_agent` value.
    referer
        The referer. If None, use `settings.http_referer` value.
    accept_language
        The accept language. If None, use `settings.http_accept_language`
        value.

    Returns
    -------
    headers
        The updated HTTP headers.
    """
    if user_agent is None:
        user_agent = settings.http_user_agent
    if referer is None:
        referer = settings.http_referer
    if accept_language is None:
        accept_language = settings.http_accept_language

    info = {"User-Agent": user_agent, "referer": referer, "Accept-Language": accept_language}
    headers = dict(requests.utils.default_headers())
    headers.update(info)
    return headers

    Update the default requests HTTP headers with OSMnx information.

    Parameters
    ----------
    user_agent
        The user agent. If None, use `settings.http_user_agent` value.
    referer
        The referer. If None, use `settings.http_referer` value.
    accept_language
        The accept language. If None, use `settings.http_accept_language`
        value.

    Returns
    -------
    headers
        The updated HTTP headers.
    
osmnx/_http.py