Generate bit.ly urls in Python

gistfile1.py

import urllib
try:
    import json
except ImportError:
    import simplejson as json

#Enter your bitly username and apikey here
BITLY_USER = 'xxxxxx'
BITLY_API = 'xxxxxxxxxxxxxxxxxxxxxxxxx'

def shorten(url):
    long_url = urllib.urlencode(dict(longUrl=url))
    login = urllib.urlencode(dict(login=BITLY_USER))
    apiKey = urllib.urlencode(dict(apiKey=BITLY_API))
    
    encodedurl="http://api.bit.ly/shorten?version=2.0.1&%s&%s&%s" % (long_url, login, apiKey)
    
    strm = urllib.urlopen(encodedurl)
    respond_dict = json.loads(strm.read())
    strm.close()
    short_url = respond_dict["results"][url]["shortUrl"]
    return short_url