Update app.py

app.py

@@ -141,6 +141,14 @@ def process_user_question(user_question):
 
     # st.empty()
 
+    try:
+        st.session_state.conversation({'question': ""})
+        # if "key" not in st.session_state:
+        #     st.write('Good')
+    except:
+        st.error("Please upload and analyze your PDF files first!")
+        return
+    
     response = st.session_state.conversation({'question': user_question})
     st.session_state.chat_history = response['chat_history']
     results_size = len(response['chat_history'])