Access to the cookies of the default browser

I want to write a program that opens the browser and open a url with a given cookie. I dont know how to do this.开发者_如何学JAVA Maybe I could modify the cookies in the default place.

import urllib2
opener = urllib2.build_opener()
opener.addheaders.append(('Cookie', 'cookiename=cookievalue'))
f = opener.open("http://example.com/")

Modules to look into:

urllib2
cookielib
Cookie

In python, you can emulate a browser with the mechanize library. Also, there is good documentation about mechanize and cookies.