[pygame] Is pygame event thread save? or I need use lock to post user event in thread?

[halida]

I want to use multi-thread in pygame game loop,
with main draw and display.update thread,
 event process thread,
game update thread.
and I will use event.post(drawEvent) to tell main thread  to update
screen.
do I need use threading.Lock()  to lock it? or just let it go?
it is too hard to read pygame source code for me.