def processEnded(reason):
        """
        Called when the child process exits and all file descriptors associated
        with it have been closed.

        @type reason: L{twisted.python.failure.Failure}
        @param reason: A failure giving the reason the child process
            terminated.  The type of exception for this failure is either
            L{twisted.internet.error.ProcessDone} or
            L{twisted.internet.error.ProcessTerminated}.
        """

        Called when the child process exits and all file descriptors associated
        with it have been closed.

        @type reason: L{twisted.python.failure.Failure}
        @param reason: A failure giving the reason the child process
            terminated.  The type of exception for this failure is either
            L{twisted.internet.error.ProcessDone} or
            L{twisted.internet.error.ProcessTerminated}.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/internet/interfaces.py