Django:请帮助，我得到了is_valid()缺少一个必需的位置参数:'self' .下面是代码块…谢谢

 class ContentCreateUpdateView(TemplateResponseMixin, View):
    module = None
    model = None
    obj = None
    template_name = 'courses/manage/content/form.html'

    def get_model(self, model_name):
       if model_name in ['text', 'video', 'image', 'file']:
           return apps.get_model(app_label='courses', model_name=model_name)
       return None 
    def get_form(self, model, *args, **kwargs):
        Form = modelform_factory(model, exclude=['owner', 'order', 'created', 'updated'])
        return Form

    def dispatch(self, request, module_id, model_name, id=None):
        self.module = get_object_or_404(Module, id=module_id, course__owner=request.user)
        self.model = self.get_model(model_name)
        if id:
            self.obj = get_object_or_404(self.model, id=id, owner=request.user)

        return super(ContentCreateUpdateView, self).dispatch(request, module_id, model_name, id)

    def get(self, request, module_id, model_name, id=None):
        form = self.get_form(self.model, instance=self.obj)
        return self.render_to_response({'form': form, 'object': self.obj})

    def post(self, request, module_id, model_name, id=None):
        form = self.get_form(self.model, instance=self.obj, data=request.POST, files=request.FILES)
        if form.is_valid():
            obj = form.save(commit=False)
            obj.owner = request.user
            obj.save()
            if not id:
                # new content
                Content.objects.create(module=self.module, item=obj)

            return redirect('module_content_list', self.module.id)
        return self.render_to_response({'form': form, 'object': self.obj})
 class ContentCreateUpdateView(TemplateResponse