Restrict mt:quiz template to :Exercice instances

tetras_extraction/macao_12/script/templates/quiz.rq

@@ -13,18 +13,9 @@ template mt:quiz(?quiz) {
         ']'
     }
     '}'
-#     format {
-#         """
-# {
-#     "elements": [
-#         %s
-#     ]
-# }
-#         """
-#         box { st:call-template(mt:qcu, ?quiz) }
-#     }
 }
 where {
+    ?quiz a :Exercice
     ?quiz :id ?id .
 }