This is some suggested additional material for the 
urllib2 docs.

Particularly the part about error codes and the 
reason/code attributes of error objects is *missing* from 
the manual and needed.

Also the example showing basic Authentication using 
password manager/handler/opener may help avoid some 
confusion.

Alternatively you can link to my online tutorials at 
http://www.voidspace.org.uk/python/articles.shtml#http

:-)