code: def get_success_url(self):
          
          if not self.success_url:
              if self.request.GET.get("inmodal"):
                  return reverse("arctic:redirect_to_parent")
              raise ImproperlyConfigured(
                  "No URL to redirect to. Provide a success_url."
              )
          return self.in_modal(str(self.success_url))
docs: Return the URL to redirect to after processing a valid form.