def file_groups(self):
        """
        List the ``USE`` attributes of all ``mets:fileGrp``.
        """
        return [el.get('USE') for el in self._tree.getroot().findall('.//mets:fileGrp', NS)]
def file_groups ( self ) : return [ el . get ( 'USE' ) for el in self . _tree . getroot ( ) . findall ( './/mets:fileGrp' , NS ) ]
List the ``USE`` attributes of all ``mets:fileGrp``.