def static_url_path(self) -> str | None:
        """The URL prefix that the static route will be accessible from.

        If it was not configured during init, it is derived from
        :attr:`static_folder`.
        """
        if self._static_url_path is not None:
            return self._static_url_path

        if self.static_folder is not None:
            basename = os.path.basename(self.static_folder)
            return f"/{basename}".rstrip("/")

        return None
The URL prefix that the static route will be accessible from.

        If it was not configured during init, it is derived from
        :attr:`static_folder`.
        
src/flask/sansio/scaffold.py