def childConnectionLost(childFD):
        """
        Called when a file descriptor associated with the child process is
        closed.

        @type childFD: C{int}
        @param childFD: The file descriptor which was closed.
        """

        Called when a file descriptor associated with the child process is
        closed.

        @type childFD: C{int}
        @param childFD: The file descriptor which was closed.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/internet/interfaces.py