'Advance to the next result set.
Returns None if there are no more result sets.'

def nextset(self):

    if self._executed:
        self.fetchall()
    del self.messages[:]
    db = self._get_db()
    nr = db.next_result()
    if (nr == (-1)):
        return None
    self._do_get_result()
    self._post_get_result()
    self._warning_check()
    return 1
