Change Class Base to Function Base

Can someone help me change class base to function base, I am better of function base, class base is quite confusing for me. 

Url:

path("inbox", InboxView.as_view(), name='inbox'),
re_path(r"^messages/(?P<username>[\w.@+-]+)", ThreadView.as_view(), name="messages"),

Views.py:

class InboxView(LoginRequiredMixin, ListView):
    template_name = 'inbox.html'
    def get_queryset(self):
        return Thread.objects.by_user(self.request.user)

    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)
        context['chat_list'] = Thread.objects.filter(Q(first=self.request.user)| Q(second=self.request.user))
        #Online Users
        context['online_user'] = Profile.objects.filter(friends__user=self.request.user, is_online=True)
        return context

class ThreadView(LoginRequiredMixin, FormMixin, DetailView):
    template_name = 'thread.html'
    form_class = ComposeForm
    success_url = './'

    def get_queryset(self):
        return Thread.objects.by_user(self.request.user)

    def get_object(self):
        other_username  = self.kwargs.get("username")
        obj, created    = Thread.objects.get_or_new(self.request.user, other_username)
        if obj == None:
            raise Http404
        return obj

    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)
        context['form'] = self.get_form()
        context['chat_msg'] = ChatMessage.objects.all().order_by('-timestamp')
        context['chat_list'] = Thread.objects.filter(Q(first=self.request.user)| Q(second=self.request.user))
        context['online_user'] = Profile.objects.filter(friends__user=self.request.user, is_online=True)
        return context

    def post(self, request, *args, **kwargs):
        if not request.user.is_authenticated:
            return HttpResponseForbidden()
        self.object = self.get_object()
        form = self.get_form()
        if form.is_valid():
            return self.form_valid(form)
        else:
            return self.form_invalid(form)

    def form_valid(self, form):
        thread = self.get_object()
        user = self.request.user
        message = form.cleaned_data.get("message")
        ChatMessage.objects.create(user=user, thread=thread, message=message)
        return super().form_valid(form)