def startReactor(self, reactor, oldstdout, oldstderr):
        """
        Run the reactor with the given configuration.  Subclasses should
        probably call this from C{postApplication}.

        @see: L{runReactorWithLogging}
        """
        if reactor is None:
            from twisted.internet import reactor
        runReactorWithLogging(
            self.config, oldstdout, oldstderr, self.profiler, reactor)

        if _ISupportsExitSignalCapturing.providedBy(reactor):
            self._exitSignal = reactor._exitSignal
        else:
            self._exitSignal = None

        Run the reactor with the given configuration.  Subclasses should
        probably call this from C{postApplication}.

        @see: L{runReactorWithLogging}
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/application/app.py