fix critical

bot.py

@@ -62,15 +62,13 @@ def main():
 def on_book(message: dict, state: StateManager):
     symbol = message["symbol"]
 
-    def best_price(side) -> int:
+    def best_price(side) -> int | None:
         if message[side]:
             return message[side][0][0]
-
-    bid_price = int(best_price("buy"))
-    ask_price = int(best_price("sell"))
-    print(message)
-
-    state.update_bid_ask_price(symbol, bid_price, ask_price)
+        else:
+            return None
+        
+    state.update_bid_ask_price(symbol, best_price("buy"), best_price("sell"))
 
 def on_fill(message: dict, orderman: OrderManager, state: StateManager):
     symbol = message["symbol"]