Update app.py

app.py

@@ -1,16 +1,17 @@
 """
-NWFWO Practice – Gradio MCP app for ChatGPT
+NWFWO Practice - Gradio MCP app for ChatGPT
 
-This file does two things:
 1) Runs a normal Gradio web app (for debugging in your browser)
 2) Exposes an MCP server + HTML UI card for ChatGPT Apps
 """
 
-import gradio as gr
 from dataclasses import dataclass
+from typing import Optional
+
+import gradio as gr
 
 
-# ---- 1. Data model for the “game state” ----
+# ---- 1. Data model for the "game state" ----
 
 @dataclass
 class NWFWOExample:
@@ -19,17 +20,17 @@ class NWFWOExample:
     # The correct NWFWO answer (what the learner should guess)
     correct_nwfwo: str
     # Optional: explanation to show after checking
-    explanation: str | None = None
+    explanation: Optional[str] = None
 
 
-# ---- 2. Core tool logic: check the learner’s guess ----
+# ---- 2. Core tool logic: check the learner's guess ----
 
 @gr.mcp.tool()  # exposes the function as an MCP tool to ChatGPT / MCP clients
 def check_nwfwo(
     transliteration: str,
     correct_nwfwo: str,
     user_guess: str,
-    explanation: str | None = None,
+    explanation: Optional[str] = None,
 ):
     """
     Simple checker for NWFWO practice.
@@ -69,7 +70,7 @@ def check_nwfwo(
     return result
 
 
-# ---- 3. Normal Gradio UI (handy while you’re developing) ----
+# ---- 3. Normal Gradio UI (handy while you're developing) ----
 
 def local_check_ui(transliteration, correct_nwfwo, user_guess, explanation):
     res = check_nwfwo(