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 runSpider(self, lstSubcommand=None):
        strSubcommand = lstSubcommand[0]
        strArg1 = None
        if len(lstSubcommand) == 2:
            strArg1 = lstSubcommand[1]
        self.initDriver() #init selenium driver
        self.dicSubCommandHandler[strSubcommand](strArg1)
        self.quitDriver() #quit selenium driver