threads instead od processes

Hi.

I've got a little script:

#!/usr/bin/python
import sys, os
for x in sys.argv[1:]:
pid = os.fork()
if pid == 0:
# do something with x
break

This creates some new processes (depending on the number of passed command
line arguments) and inside each process x is one command line argument.

Now my question is: How can I do the same by using threads instead of
processes?
Thank you.
Best regards

Markus Franz