def robotsrulesetOfDomain(self, domain):
		'''检查domain是否在数据库中,
			否 --> (False, None)
			是 --> (True, 数据库中存储的robots.txt内容)
		'''
		exist = False
		cur = self.conn.cursor()
		# 是否存在
		cur.execute("SELECT 1 FROM Domains WHERE domain=?", (domain,))
		if cur.fetchone() :
			exist = True
		# 存在的话,结果是什么
		cur.execute("SELECT rules FROM Domains,Rulesets "
			"WHERE domain=? AND Domains.did=Rulesets.did"
			,(domain,) )
		ruleset = cur.fetchone()
		return (exist, ruleset)
def _verify_toplevel_json(self, replay_data):
        fn = self._filename

        if "version" not in replay_data:
            raise TransactionReplayError(fn, _('Missing key "{key}".'.format(key="version")))

        self._assert_type(replay_data["version"], str, "version", "string")

        _check_version(replay_data["version"], fn)