When programming in python, using Idiomatic python is normally the way to go. One of python idioms is EAFP: Easier to ask for forgiveness than permission. So try creating a directory, if it exists you'll get an error you can catch.
example
import os, errno try: os.makedirs('my_folder') except OSError as e: # If error is not already exists, then raise the error else continue if e.errno != errno.EEXIST: raise # Now do what you want with my_folder