plpythonu and "hello concurrent world"

Hi all. Im having some "problems" with a small concurrent plpython function.

Based on a small example [1] about concurrent programming, there is some 
code which works fine under python:
#! /usr/bin/python

import threading, random
import time

def myPrint(str):   print 'searching...', str   time.sleep(random.randint(10, 10000) / 1000.0)   print str, 'OK!'

myThreads = (threading.Timer(random.random(), myPrint, ["hello"]), \               threading.Timer(random.random(),
myPrint,["concurrent"]), \               threading.Timer(random.random(), myPrint, ["world"]))
 

for thr in myThreads:   thr.start()

gherzig@linux: python pp.py
searching... concurrent
searching... world
searching... hello
hello OK!
concurrent OK!
world OK!

So far, so good. Almost the same example in plpythonu:
CREATE OR REPLACE FUNCTION search_t()
returns bigint
security definer
as
$$
import threading, random
import time

def myPrint(str):   plpy.notice ('searching...', str)   time.sleep(random.randint(10, 10000) / 1000.0)
plpy.notice(str,'OK!')
 

myThreads = (threading.Timer(random.random(), myPrint, ["hello"]), \               threading.Timer(random.random(),
myPrint,["concurrent"]), \               threading.Timer(random.random(), myPrint, ["world"]))
 

for thr in myThreads:   thr.start()

return 10000
$$ language plpythonu;

gse_new_version=# select * From search_t();search_t
----------   10000
(1 row)

Looks like myPrint() is not executing at all!!
Have no idea why, so i decided writing both on python and postgres 
forums. Any ideas??

Postgres 8.1.3
python 2.5.1

Thanks!!
Gerardo

[1]
http://forums.hostrocket.com/showthread.php?t=13325