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(cls):
        """A contextmanager which disables handling sigint in the current signal handler. This
        allows threads that are not the main thread to ignore sigint.

        NB: Only use this if you can't use ExceptionSink.trapped_signals().

        Class state:
        - Toggles `self._ignore_sigint` in `cls._signal_handler`.
        """
        with cls._signal_handler._ignoring_sigint():
            yield