o this will block forever if the
        child has unread output and has terminated. In other words, the child
        may have printed output then called exit(), but, the child is
        technically still alive until its output is read by the parent.

        This method is non-blocking if :meth:`wait` has already been called
        previously or :meth:`isalive` method returns False.  It simply returns
        the previously determined exit status.
        T)