diff --git a/arkindex_worker/worker/training.py b/arkindex_worker/worker/training.py
index 07e175f795163fb31864b7e84be62aef6733d183..5fd9e4555091d0ee5e223996841d0cd1f51c5f46 100644
--- a/arkindex_worker/worker/training.py
+++ b/arkindex_worker/worker/training.py
@@ -167,8 +167,8 @@ class TrainingMixin(object):
     def update_model_version(
         self,
         model_version_details: dict,
-        description: str = None,
-        configuration: dict = None,
+        description: str = "",
+        configuration: dict = {},
         tag: str = None,
     ) -> None:
         """