Message d'erreur qui ne parle pas de object Voeu

bda/views.py

@@ -11,6 +11,7 @@ from django.contrib import messages
 from django.contrib.auth.decorators import login_required
 from django.core import serializers
 from django.core.urlresolvers import reverse
+from django.core.exceptions import NON_FIELD_ERRORS
 from django.db import transaction
 from django.db.models import Count, Prefetch
 from django.forms.models import inlineformset_factory
@@ -188,6 +189,12 @@ def inscription(request, tirage_id):
         ChoixSpectacle,
         fields=("spectacle", "double_choice", "priority"),
         formset=InscriptionInlineFormSet,
+        can_order=True,
+        error_messages={
+            NON_FIELD_ERRORS: {
+                'unique_together': "Vous avez déjà demandé ce voeu plus haut !",
+            },
+        }
     )
 
     if request.method == "POST":