fix iterator

app.py

@@ -154,9 +154,9 @@ def retriever(query: str, selected_retriever: str):
 
     for idx, document in enumerate(topk_documents):
         try:
-            idx = document.lower().index("abstract:")
-            title = document[:idx].replace('\n', ' ')
-            doc_details = document[idx:]
+            a_idx = document.lower().index("abstract:")
+            title = document[:a_idx].replace('\n', ' ')
+            doc_details = document[a_idx:]
             with st.expander(f"Rank {ix+1} - {title}"):
                 st.markdown(f"{doc_details}")
         except: