Update app.py

app.py

@@ -102,7 +102,10 @@ def main():
 
 
     if "messages" not in st.session_state:
-        st.session_state.messages = None
+    st.session_state["messages"] = [
+        {"role": "assistant", "content": "Hi, I'm a chatbot who can search the web. How can I help you?"}
+    ]
+
 
     st.set_page_config(page_title="Chat with multiple PDFs",
                        page_icon=":books:")