code: def require_auth(view_func):
      
      from horizon.exceptions import NotAuthenticated
  
      @functools.wraps(view_func, assigned=available_attrs(view_func))
      def dec(request, *args, **kwargs):
          if request.user.is_authenticated:
              return view_func(request, *args, **kwargs)
          raise NotAuthenticated(_("Please log in to continue."))
      return dec
docs: Performs user authentication check.
  
      Similar to Django's `login_required` decorator, except that this throws
      :exc:`~horizon.exceptions.NotAuthenticated` exception if the user is not
      signed-in.