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 __init__(self, choices=None, optional=False):
        super().__init__(
            minimum=0, maximum=2 ** 16 - 1, choices=choices, optional=optional
        )