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

        @type reason: L{twisted.python.failure.Failure}
        """

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

        @type reason: L{twisted.python.failure.Failure}
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/internet/protocol.py