Update retrieval_engine.py

retrieval_engine.py

@@ -122,7 +122,7 @@ class RetrievalEngine:
     ) -> List[RetrievedChunk]:
         
         if not self.rows:
-        return []
+            return []
 
     combined_query = clean_math_text(query)
     normalized_topic = (topic or "").strip().lower()