fix bug

py-client/libs/order.py

@@ -35,6 +35,7 @@ class OrderBook:
     def __init__(
         self, order_prefix: str, lock_timeout_sec: int = 180, cancel_timeout_sec: float = 30
     ) -> None:
+        self.order_prefix = order_prefix
         self.lock_timeout_sec = max(1, lock_timeout_sec)
         self.cancel_timeout_sec = timedelta(seconds=cancel_timeout_sec)
         self.data: list[OrderItem] = []