def get_last_tid(self):
        try:
            spec = {'tid': {'$gt': 0}}
            sort = [('tid', -1)]
            row = self.db.docs.find_one(spec, sort=sort)
        except Exception as e:
            raise DatabaseException(e)
        if row:
            return row['tid']
        return 0
def _rematcher(regex):
    """compile the regexp with the best available regexp engine and return a
    matcher function"""
    m = util.re.compile(regex)
    try:
        # slightly faster, provided by facebook's re2 bindings
        return m.test_match
    except AttributeError:
        return m.match