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 _ignoring_sigint(self):
        with self._ignore_sigint_lock:
            self._check_sigint_gate_is_correct()
            self._threads_ignoring_sigint += 1
        try:
            yield
        finally:
            with self._ignore_sigint_lock:
                self._threads_ignoring_sigint -= 1
                self._check_sigint_gate_is_correct()