improve retrieved document parsing

app.py

@@ -146,8 +146,12 @@ def retriever(query: str, selected_retriever: str):
 
         retrieved_document_titles = ""
         for document in topk_documents:
-            title = document[:document.lower().index("abstract: ")].replace('\n', ' ')
-            retrieved_document_titles = f"{retrieved_document_titles}\n"
+            try:
+                idx = document.lower().index("abstract: ")
+                title = document[:idx].replace('\n', ' ')
+                retrieved_document_titles = retrieved_document_titles + title + '\n'
+            except:
+                retrieved_document_titles = retrieved_document_titles + document + '\n'
 
         display_retrieved_documents = f"\nRetrieved Documents: \n{retrieved_document_titles}"