banging my head on Streamlit

app.py

@@ -26,7 +26,9 @@ while True:
         st.session_state['messages'].append("Tick.")
         line = child.readline()
         st.session_state['messages'].append(line)
-        if ">>>>>" in line: child.sendline("Hello")
+        if ">>>>>" in line:
+            user_input = st.text_input("Enter your message here:")
+            if user_input : child.sendline(user_input)