Call delete rich menu API.

        https://developers.line.me/en/docs/messaging-api/reference/#delete-rich-menu

        :param str rich_menu_id: ID of an uploaded rich menu
        :param timeout: (optional) How long to wait for the server
            to send data before giving up, as a float,
            or a (connect timeout, read timeout) float tuple.
            Default is self.http_client.timeout
        :type timeout: float | tuple(float, float)

def delete_rich_menu(self, rich_menu_id, timeout=None):
        """Call delete rich menu API.

        https://developers.line.me/en/docs/messaging-api/reference/#delete-rich-menu

        :param str rich_menu_id: ID of an uploaded rich menu
        :param timeout: (optional) How long to wait for the server
            to send data before giving up, as a float,
            or a (connect timeout, read timeout) float tuple.
            Default is self.http_client.timeout
        :type timeout: float | tuple(float, float)
        """
        self._delete(
            '/v2/bot/richmenu/{rich_menu_id}'.format(rich_menu_id=rich_menu_id),
            timeout=timeout
        )