def _delete_whitespace ( self ) : while isinstance ( self . _lines [ - 1 ] , ( self . _Space , self . _LineBreak , self . _Indent ) ) : del self . _lines [ - 1 ]
python clear leading whitespace
Delete all whitespace from the end of the line .
def _delete_whitespace(self):
        """Delete all whitespace from the end of the line."""
        while isinstance(self._lines[-1], (self._Space, self._LineBreak,
                                           self._Indent)):
            del self._lines[-1]