diff --git a/application/retriever/retriever_creator.py b/application/retriever/retriever_creator.py
index 07be373d..26cb41ca 100644
--- a/application/retriever/retriever_creator.py
+++ b/application/retriever/retriever_creator.py
@@ -3,18 +3,18 @@ from application.retriever.duckduck_search import DuckDuckSearch
 from application.retriever.brave_search import BraveRetSearch
 
 
-
 class RetrieverCreator:
     retrievers = {
-        'classic': ClassicRAG,
-        'duckduck_search': DuckDuckSearch,
-        'brave_search': BraveRetSearch,
-        'default': ClassicRAG
+        "classic": ClassicRAG,
+        "duckduck_search": DuckDuckSearch,
+        "brave_search": BraveRetSearch,
+        "default": ClassicRAG,
     }
 
     @classmethod
     def create_retriever(cls, type, *args, **kwargs):
-        retiever_class = cls.retrievers.get(type.lower())
+        retriever_type = (type or "default").lower()
+        retiever_class = cls.retrievers.get(retriever_type)
         if not retiever_class:
             raise ValueError(f"No retievers class found for type {type}")
-        return retiever_class(*args, **kwargs)
\ No newline at end of file
+        return retiever_class(*args, **kwargs)