def wait(self):
        '''This waits until the child exits. This is a blocking call. This will
        not read any data from the child, so 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.
        '''

        ptyproc = self.ptyproc
        with _wrap_ptyprocess_err():
            # exception may occur if "Is some other process attempting
            # "job control with our child pid?"
            exitstatus = ptyproc.wait()
        self.status = ptyproc.status
        self.exitstatus = ptyproc.exitstatus
        self.signalstatus = ptyproc.signalstatus
        self.terminated = True

        return exitstatus
This waits until the child exits. This is a blocking call. This will
        not read any data from the child, so 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.