NoReverseMatch в / cpp / 1 / view / Error, после добавления <a href="{% url 'jmiforums:answer' subforum.subform_name ques.id %}"> ответа </a>

Question

ошибка:

NoReverseMatch at /cpp/1/view/

Reverse for 'answer' with arguments '('', 1)' not found. 1 pattern(s) tried: ['(?P<subforum_name>[-a-zA-Z0-9_]+)\\/(?P<ques_id>[0-9]+)\\/answer\\/$']

urls.py:

path("<slug:subforum_name>/<int:ques_id>/view/", views.view_question, name="view_question"),
path("<slug:subforum_name>/<int:ques_id>/answer/", views.answer, name='answer'),

views.py:

def view_question(request, subforum_name, ques_id):
  ques = Question.objects.get(pk=ques_id)
  subforum = Subforum.objects.get(subforum_name=subforum_name)
  ans = Answer.objects.filter(ques_id=ques_id).values()
  com = Comment.objects.filter(ques_id=ques_id).values()
  form2 = Comments(request.POST or None)
  if form2.is_valid():
    comment = form.save(commit=False)
    comment.user_id = User.objects.get(pk=request.user.pk)
    comment.ques_id = Question.objects.get(pk=ques_id)
    comment.save()
   return HttpResponseRedirect("/{subforum_name}/{ques_id}/view".format(subforum_name=subforum_name, ques_id=ques_id))

  context = {
    'ques': ques,
    'subforum': subforum,
    'ans': ans,
    'com': com,
    'form2': form2,
  }
  return render(request, 'jmiforums/view_question.html', context)    

view_question.html:

   <a href="{% url 'jmiforums:answer' subforum.subform_name ques.id %}">Answer</a>

Я думаю, что проблема в ссылке view_question.html, но не знаю что. Заранее спасибо.