def reverse_url(self, name: str, *args: Any) -> str:
        """Returns a URL path for handler named ``name``

        The handler must be added to the application as a named `URLSpec`.

        Args will be substituted for capturing groups in the `URLSpec` regex.
        They will be converted to strings if necessary, encoded as utf8,
        and url-escaped.
        """
        reversed_url = self.default_router.reverse_url(name, *args)
        if reversed_url is not None:
            return reversed_url

        raise KeyError("%s not found in named urls" % name)