code: def anonymous_user_required(*decorator_args, msg=None, category=None, redirect_url=None):
      
      def wrapper(fn):
          @wraps(fn)
          def decorated(*args, **kwargs):
              if current_user.is_authenticated:
                  if request.is_json:
                      abort(HTTPStatus.FORBIDDEN)
                  else:
                      if msg:
                          flash(msg, category)
                      return redirect('SECURITY_POST_LOGIN_REDIRECT_ENDPOINT',
                                      override=redirect_url)
              return fn(*args, **kwargs)
          return decorated
  
      if decorator_args and callable(decorator_args[0]):
          return wrapper(decorator_args[0])
      return wrapper
docs: Decorator requiring that there is no user currently logged in.
  
      Aborts with ``HTTP 403: Forbidden`` if there is an authenticated user.