def script_name(self, path=None):
        """Return the script_name of the app at the given path, or None.

        If path is None, cherrypy.request is used.
        """
        if path is None:
            try:
                request = cherrypy.serving.request
                path = httputil.urljoin(request.script_name, request.path_info)
            except AttributeError:
                return None

        while True:
            if path in self.apps:
                return path

            if path == '':
                return None

            # Move one node up the tree and try again.
            path = path[: path.rfind('/')]
Return the script_name of the app at the given path, or None.

        If path is None, cherrypy.request is used.
        
cherrypy/_cptree.py