async django CBV methods post in class CreateVIew

I am need help in using async to python django in base class view.

class IndexPage(CreateView):
    """Page index site"""

    async def post(self, request, *args, **kwargs) -> object:
                await send_code(data['email'])
                return render(request, 'activate.html')
        return super().post(request, *args, **kwargs)

If you create this function simply as a function without a class, everything works fine, but an error occurs when using the class:

IndexPAge HTTP handlers must either be all sync or all async.

Please help anyone who has encountered this problem, thank you.

class Test(CreateView):
    template_name = 'index.html'
    form_class = TestForm
    view_is_async = True # on async