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 _resetExpect(self):
        self.previousExpectLine = ""
        if self._connection is not None and isinstance(self._connection.buffer, str):
            self.previousExpectLine = self._connection.buffer 
            self._connection.buffer = ""