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