def cancel_all(self, product_id=None):
        """ With best effort, cancel all open orders.

        Args:
            product_id (Optional[str]): Only cancel orders for this
                product_id

        Returns:
            list: A list of ids of the canceled orders. Example::
                [
                    "144c6f8e-713f-4682-8435-5280fbe8b2b4",
                    "debe4907-95dc-442f-af3b-cec12f42ebda",
                    "cf7aceee-7b08-4227-a76c-3858144323ab",
                    "dfc5ae27-cadb-4c0c-beef-8994936fde8a",
                    "34fecfbf-de33-4273-b2c6-baf8e8948be4"
                ]

        """
        if product_id is not None:
            params = {'product_id': product_id}
        else:
            params = None
        return self._send_message('delete', '/orders', params=params)
 With best effort, cancel all open orders.

        Args:
            product_id (Optional[str]): Only cancel orders for this
                product_id

        Returns:
            list: A list of ids of the canceled orders. Example::
                [
                    "144c6f8e-713f-4682-8435-5280fbe8b2b4",
                    "debe4907-95dc-442f-af3b-cec12f42ebda",
                    "cf7aceee-7b08-4227-a76c-3858144323ab",
                    "dfc5ae27-cadb-4c0c-beef-8994936fde8a",
                    "34fecfbf-de33-4273-b2c6-baf8e8948be4"
                ]

        
cbpro/authenticated_client.py