def _makeHelperReactor(self):
        """
        Create and (in a new thread) start a L{Win32Reactor} instance to use for
        the implementation of L{IReactorWin32Events}.
        """
        self._reactor = Win32Reactor()
        # This is a helper reactor, it is not the global reactor and its thread
        # is not "the" I/O thread.  Prevent it from registering it as such.
        self._reactor._registerAsIOThread = False
        self._reactorThread = Thread(
            target=self._reactor.run, args=(False,))
        self.addSystemEventTrigger(
            'after', 'shutdown', self._unmakeHelperReactor)
        self._reactorThread.start()

        Create and (in a new thread) start a L{Win32Reactor} instance to use for
        the implementation of L{IReactorWin32Events}.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/internet/win32eventreactor.py