# buspred.py

import urllib
busurl = "http://ctabustracker.com/bustime/"\
         "map/getStopPredictions.jsp"

def bus_predictions(route,stop):
    fields = {'route': route,
              'stop': stop }
    parms = urllib.urlencode(fields)
    u = urllib.urlopen(busurl+"?"+parms)
    return u.read()

print bus_predictions(6,5037)