mark known absence of weddings as -

src/authentic2_auth_fedict/adapters.py

@@ -65,6 +65,9 @@ class AuthenticAdapter(DefaultAdapter):
         if 'lieuxMariage' in attributes:
             # change from list to string
             attributes['lieuxMariage'] = '|'.join(attributes.get('lieuxMariage'))
+            if not attributes['lieuxMariage']:
+                # special case "no wedding"
+                attributes['lieuxMariage'] = '-'
 
         # assume all answers are for Belgium, this may not actually be true
         attributes['pays'] = 'Belgique'