18.22.1 CookieJar and FileCookieJar Objects  CookieJar objects
support the iterator protocol for iterating over contained
Cookie objects.  CookieJar has the following methods:
add_cookie_header( request) Add correct Cookie: header to
request.  If policy allows (ie. the rfc2965 and hide_cookie2
attributes of the CookieJar's CookiePolicy instance are true and
false respectively), the Cookie2: header is also added when
appropriate.  The request object (usually a urllib2.Request
instance) must support the methods get_full_url(), get_host(),
get_type(), unverifiable(), get_origin_req_host(), has_header(),
get_header(), header_items(), and add_unredirected_header(),as
documented by urllib2.  extract_cookies( response, request)
Extract cookies from HTTP response and store them in the
CookieJar, where allowed by policy.  The CookieJar will look for
allowable Set-Cookie: and Set-Cookie2: headers in the response
argument, and store cookies as appropriate (subject to the
CookiePolicy.set_ok() method's approval).  The r