diff --git a/luxonis_ml/data/datasets/luxonis_dataset.py b/luxonis_ml/data/datasets/luxonis_dataset.py
index 17b7917a..9c7de0ac 100644
--- a/luxonis_ml/data/datasets/luxonis_dataset.py
+++ b/luxonis_ml/data/datasets/luxonis_dataset.py
@@ -345,7 +345,7 @@ def merge_with(
         self,
         other: "LuxonisDataset",
         inplace: bool = True,
-        new_dataset_name: str = None,
+        new_dataset_name: Optional[str] = None,
     ) -> "LuxonisDataset":
         """Merge all data from `other` LuxonisDataset into the current
         dataset (in-place or in a new dataset).