old_contents: from django.contrib.auth import logout
  from django.core.urlresolvers import reverse
  from django.shortcuts import redirect
  from django.views.generic import View
  
  
  class LogoutView(View):
  
      def get(self, request, *args, **kwargs):
          logout(request)
          return redirect(reverse("login"))
  
new_contents: from django.contrib import messages
  from django.contrib.auth import logout
  from django.core.urlresolvers import reverse
  from django.shortcuts import redirect
  from django.views.generic import View
  
  
  class LogoutView(View):
  
      def get(self, request, *args, **kwargs):
          logout(request)
          messages.add_message(
              request,
              messages.SUCCESS,
              "성공적으로 로그아웃 되었습니다",
          )
          return redirect(reverse("login"))
  
subject: update LogoutView: add success logout flash message