[FIX]Bug if no contact mail filled

services/operation_services.py

@@ -631,7 +631,7 @@ class OperationsService(Component):
             "role": role,
             "id": operation.id,
             "name": operation.name,
-            "email": operation.sudo().mail_contact,
+            "email": operation.sudo().mail_contact or "",
         }
 
         return datas
@@ -737,7 +737,7 @@ class OperationsService(Component):
             },
             "id": {"type": "integer"},
             "name": {"type": "string"},
-            "email": {"type": "string"},
+            "email": {"type": "string", "nullable": True},
         }
 
     def _validator_get_doc(self):