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 call_process(cls, cmd):
        if cls.is_error:
            raise subprocess.CalledProcessError(-1, cmd=cmd, output="Couldn't call xset.")

        if cmd[1:] == ["q"]:
            track = cls.info[cls.index]
            output = "\n".join(track)
            return output