def insertRuleset(self, ruleset, domain):
		'''增加一个robots.txt规则集'''
		cur = self.conn.cursor()
		cur.execute("SELECT did FROM Domains WHERE domain=?", (domain,))
		did = cur.fetchone()[0]
		cur.execute("INSERT INTO Rulesets VALUES (NULL,?,?)",(did, ruleset))
		# 写入到文件
		self.conn.commit()
def literal_eval(node_or_string):
    if isinstance(node_or_string, AST):
        node_or_string = gast_to_ast(node_or_string)
    return _ast.literal_eval(node_or_string)