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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def validate_cookies(session, class_name):
 """ Checks whether we have all the required cookies to authenticate on class.coursera.org. Also check for and remove stale session. """

    if not do_we_have_enough_cookies(session.cookies, class_name):
        return False

    url = CLASS_URL.format(class_name=class_name) + '/class'
    r = session.head(url, allow_redirects=False)

    if r.status_code == 200:
        return True
    else:
        logging.debug('Stale session.')
        try:
            session.cookies.clear('.coursera.org')
        except KeyError:
            pass
        return False