Django InlineFormset with GCBV (Generic Class Based Views)

class QuestionCreateView(LoginRequiredMixin, CreateView):
    question_type       =   ""
    template_name       =   "courses/question_form.html"
    #pk_url_kwarg       =   "quiz_pk"
    #context_object_name =  "quiz"

    def dispatch(self, request, *args, **kwargs):
        self.question_type =    kwargs.get('question_type')
        # call the view
        return super().dispatch(request, *args, **kwargs)

    def get_form(self, form_class=None):
        if self.question_type == 'tf':
            form_class =    forms.TrueFalseQuestionForm
        else:
            form_class =    forms.MultipleChoiceQuestionForm

        return form_class(**self.get_form_kwargs())

    def get(self, request, *args, **kwargs):
        self.object     =   None
        if self.question_type == 'tf':
            return self.render_to_response(self.get_context_data())
        else:
            answer_forms    =   forms.AnswerInlineFormSet(
                queryset=models.Answer.objects.none()
            )
            return self.render_to_response(self.get_context_data(formset=answer_forms))

    def post(self, request, *args, **kwargs):
        #self.object    =   None
        form            =   self.get_form()
        if self.question_type == 'tf':
            if form.is_valid():
                return self.form_valid(form)
            else:
                return self.form_invalid(form)
        else:
            answer_forms    =   forms.AnswerInlineFormSet(
                request.POST,
                queryset=models.Answer.objects.none()
            )
            if form.is_valid() and answer_forms.is_valid():
                return self.form_valid(form, answer_forms)
            else:
                return self.form_invalid(form, answer_forms)

    def form_valid(self, form, formset=None):
        if self.question_type == 'tf':
            return super().form_valid(form)
        else:
            question            =   form.save(commit=False)
            question.quiz_id    =   self.kwargs['quiz_pk']
            question.save()

            answers             =   formset.save(commit=False)
            for answer in answers:
                answer.question =   question
                answer.save() 
            return super().form_valid(form) #equals to return HttpResponseRedirect(self.get_success_url())

    def get_context_data(self, **kwargs):
        ''' only used for the page title '''
        context             =   super().get_context_data(**kwargs)
        context['quiz']     =   models.Quiz.objects.get(id=self.kwargs['quiz_pk'])
        return context