diff --git a/doc/Shop.py b/doc/Shop.py
index ad969dae..b94d0b26 100644
--- a/doc/Shop.py
+++ b/doc/Shop.py
@@ -109,7 +109,7 @@ class Shop(object):
                 ],
                 'response': [
                     _common.RspHead(),
-                    ['ret', Union([
+                    ['ret', _common.Union([
                         [_common.ShopTrans(), '链上交易结果'],
                     ]), '购买结果'],
                     ['award', _common.Award(), '奖励信息'],