diff --git a/src/Python/asst/asst.py b/src/Python/asst/asst.py
index b53339442f..45f3bf5f2d 100644
--- a/src/Python/asst/asst.py
+++ b/src/Python/asst/asst.py
@@ -86,14 +86,15 @@ class Asst:
             ``callback``:   回调函数
             ``arg``:        自定义参数
         """
-
+        self.__callback = callback
         if callback:
             self.__ptr = Asst.__lib.AsstCreateEx(callback, arg)
         else:
             self.__ptr = Asst.__lib.AsstCreate()
 
     def __del__(self):
-        Asst.__lib.AsstDestroy(self.__ptr)
+        if self.__callback:
+            Asst.__lib.AsstDestroy(self.__ptr)
         self.__ptr = None
 
     def set_instance_option(self, option_type: InstanceOptionType, option_value: str):
diff --git a/src/Python/asst/utils.py b/src/Python/asst/utils.py
index 4f28428f6a..f65e0ca05e 100644
--- a/src/Python/asst/utils.py
+++ b/src/Python/asst/utils.py
@@ -24,6 +24,10 @@ class Message(Enum):
 
     AllTasksCompleted = auto()
 
+    AsyncCallInfo = auto()
+
+    Destroyed = auto()
+
     TaskChainError = 10000
 
     TaskChainStart = auto()