Launch a shell command with in a python script, wait for the termination and return to the script

I have a python script that has to launch a shell command for every file in a dir:

import os

files = os.listdir(".")
for f in files:
    os.execlp("myscript", "myscript", f)

This works fine for the first file, but after the "myscript" command has ended, the execution stops and does not come back to the python script.

How can I do this? Do I have to fork() before calling os.execlp()?