code: def save_predefined(self, predefined, client=None):
          
          predefined = self.validate_predefined(predefined)
          self._save(None, predefined, client)
docs: Save this ACL for the current bucket using a predefined ACL.
  
          If :attr:`user_project` is set, bills the API request to that project.
  
          :type predefined: str
          :param predefined: An identifier for a predefined ACL.  Must be one
                             of the keys in :attr:`PREDEFINED_JSON_ACLS`
                             or :attr:`PREDEFINED_XML_ACLS` (which will be
                             aliased to the corresponding JSON name).
                             If passed, `acl` must be None.
  
          :type client: :class:`~google.cloud.storage.client.Client` or
                        ``NoneType``
          :param client: Optional. The client to use.  If not passed, falls back
                         to the ``client`` stored on the ACL's parent.