fixed streaming error

app.py

@@ -1,9 +1,9 @@
+import io
 import streamlit as st
 import pandas as pd
 import requests
 import json
 import time
-import io
 
 st.title("Transaction Summarizer")
 
@@ -146,7 +146,7 @@ with tab2:
                     st.write(df)
 
                     # Prepare the summarized data for download
-                    csv_buffer = io.StringIO()
+                    csv_buffer = io.BytesIO()
                     df.to_csv(csv_buffer, index=False)
                     csv_buffer.seek(0)