_thread not working

[kjm]

I'm trying to figure out how to abandon a function call after 5s if the function hasn't returned a value by then.

import _thread, time

def _function(this, that):
  print('waiting for _function'); time.sleep(9); print("don't want to see this message")

_thread.start_new_thread(_function, (1, 2))
lock=_thread.allocate_lock()
lock.acquire(1, 5)

gives

Running C:\Users\Kris\Google Drive\My Documents\Pycom\main\test.py

>>>
>>>
waiting for _function
>
Pycom MicroPython 1.18.1.r7 [v1.8.6-849-d1c5ea9] on 2018-12-17; GPy with ESP32
Type "help()" for more information.
>>>
>>> don't want to see this message

isn't forcing the function to exit after 5s. Can someone show me how to achieve this?