gestion des cookies FB dans le cas d'un DL simple

src/agenda_culturel/import_tasks/extractor_facebook.py

@@ -303,6 +303,8 @@ class FacebookEventExtractor(Extractor):
             return self.get_structure()
         else:
             logger.warning("cannot find any event in page")
-
+            raise Exception(
+                    _("Cannot get Facebook event from {}").format(url)
+                )
 
         return None