def insertDomain(self, domain, indegree=0, outdegree=0):
		'''增加一个域名'''
		cur = self.conn.cursor()
		cur.execute("INSERT INTO Domains VALUES (NULL,?,?,?)", (domain, indegree, outdegree))
		# 写入到文件中
		self.conn.commit()
def warn(txt, act, opt):
    if opt.get('display_examples'):
        print(txt + ":\n" + str(act))
    else:
        warn_once(txt)