# How can I determine if anything at the given url exists
# https://stackoverflow.com/a/1966141/5983691
# 
# 4xx status codes describe client errors (like "404 Not found") 
# 5xx status codes describe server errors (like "500 Internal server error")

from urllib2 import urlopen

code = urlopen("http://example.com/").code
if (code / 100 >= 4):
   print "Nothing there."