code: def _get_redirect_url(self, request):
          
          if 'next' in request.session:
              next_url = request.session['next']
              del request.session['next']
          elif 'next' in request.GET:
              next_url = request.GET.get('next')
          elif 'next' in request.POST:
              next_url = request.POST.get('next')
          else:
              next_url = request.user.get_absolute_url()
          if not next_url:
              next_url = '/'
          return next_url
docs: Next gathered from session, then GET, then POST,
          then users absolute url.