diff --git a/Lib/subprocess.py b/Lib/subprocess.py
index 80a60b9..11fc439 100644
--- a/Lib/subprocess.py
+++ b/Lib/subprocess.py
@@ -628,7 +628,7 @@
         return data
 
 
-    def __del__(self):
+    def __del__(self, sys=sys):
         if not self._child_created:
             # We didn't get to successfully create a child process.
             return