Minor fix

app.py

@@ -39,7 +39,7 @@ def store_embeddings(pdf_path, chunk_size, chunk_overlap):
 
     index = pc.Index(host="https://langchain-test-index-la2n80y.svc.aped-4627-b74a.pinecone.io")
 
-    if index.list():
+    if index.describe_index_stats()['total_vector_count'] > 0:
         index.delete(delete_all=True)
 
     chroma_db = Chroma.from_documents(documents, embeddings, persist_directory="./chroma_db")