diff --git a/chat/src/handlers/opensearch_neural_search.py b/chat/src/handlers/opensearch_neural_search.py
index 09b59cb2..7016bccc 100644
--- a/chat/src/handlers/opensearch_neural_search.py
+++ b/chat/src/handlers/opensearch_neural_search.py
@@ -9,10 +9,10 @@ class OpenSearchNeuralSearch(VectorStore):
 
     def __init__(
         self,
-        client: None,
         endpoint: str,
         index: str,
         model_id: str,
+        client: OpenSearch = None,
         vector_field: str = "embedding",
         search_pipeline: str = None,
         text_field: str = "id",