def logout():
    """
    When the user accesses this route they are logged out.
    """

    cas_username_session_key = current_app.config['CAS_USERNAME_SESSION_KEY']
    cas_attributes_session_key = current_app.config['CAS_ATTRIBUTES_SESSION_KEY']

    if cas_username_session_key in flask.session:
        del flask.session[cas_username_session_key]

    if cas_attributes_session_key in flask.session:
        del flask.session[cas_attributes_session_key]

    if(current_app.config['CAS_AFTER_LOGOUT'] is not None):
        redirect_url = create_cas_logout_url(
            current_app.config['CAS_SERVER'],
            current_app.config['CAS_LOGOUT_ROUTE'],
            current_app.config['CAS_AFTER_LOGOUT'])
    else:
        redirect_url = create_cas_logout_url(
            current_app.config['CAS_SERVER'],
            current_app.config['CAS_LOGOUT_ROUTE'])

    current_app.logger.debug('Redirecting to: {0}'.format(redirect_url))
    return flask.redirect(redirect_url)
When the user accesses this route they are logged out.