Update app.py

Fix error:

AttributeError: st.session_state has no attribute "u_id". Did you forget to initialize it? More info: https://docs.streamlit.io/library/advanced-features/session-state#initialization

app.py

@@ -122,10 +122,10 @@ static_layout_top()
 # User plays collecting            
 inp = st.text_input("Enter your expression here: ").replace(" ", "")
 if st.button("Try your luck!"):
-    if st.session_state.u_id:
-        check_ans_user(inp)
-    else:
-        check_ans_default(inp)
+    #if st.session_state.u_id:
+    #    check_ans_user(inp)
+    #else:
+    check_ans_default(inp)
         
 #st.write(st.session_state.ans) #-- local testing only
 # Display session answers