def cache_control(self) -> RequestCacheControl:
        """A :class:`~werkzeug.datastructures.RequestCacheControl` object
        for the incoming cache control headers.
        """
        cache_control = self.headers.get("Cache-Control")
        return parse_cache_control_header(cache_control, None, RequestCacheControl)
A :class:`~werkzeug.datastructures.RequestCacheControl` object
        for the incoming cache control headers.
        
src/werkzeug/sansio/request.py