code: def login_required(self, fresh=False, redirect_to=None):
          
          if not self.logged_in() or (fresh and not self.login_manager.login_fresh()):
              if redirect_to:
                  resp = redirect(redirect_to)
              else:
                  resp = self.login_manager.unauthorized()
              current_context.exit(resp, trigger_action_group="missing_user")
docs: Ensures that a user is authenticated