code: def clear_session(self, response):
          
          session.clear()
  
          # if flask-login is installed, we try to clear the
          # "remember me" cookie, just in case it is set
          if 'flask_login' in sys.modules:
              remember_cookie = current_app.config.get('REMEMBER_COOKIE',
                                                       'remember_token')
              response.set_cookie(remember_cookie, '', expires=0, max_age=0)
docs: Clear the session.
  
          This method is invoked when the session is found to be invalid.
          Subclasses can override this method to implement a custom session
          reset.