cpebble

import praw, subprocess
SUBREDDIT = "wallpapers"
r = praw.Reddit(client_id="",
                client_secret="",
                user_agent="WallpaperGrabber by /u/ParanoidBox")
allowedFormats = ['jpg', 'png']
urls = [post.url for post in r.subreddit(SUBREDDIT).hot() if post.url.split(".")[-1] in allowedFormats]
subprocess.call(['feh', "--bg-fill", urls[0])