Fix typing complaint in boutique.views

boutique/views.py

@@ -315,7 +315,7 @@ class ManageCategoryView(PermissionRequiredMixin, ListView, ModelFormMixin):  #
     object = None
 
     def post(self, request: HttpRequest, *args, **kwargs) -> HttpResponse:
-        self.object_list = self.get_queryset()
+        self.object_list = self.get_queryset()  # type: ignore  # A QuerySet is a Sequence
         form = self.get_form()
         if form.is_valid():
             return self.form_valid(form)