diff --git a/lib/cmdlib.py b/lib/cmdlib.py
index ba71124943c5f4741bfeb6fdb1a87069c20d199d..3a5d816b5faa455a18d9ac18cebd54ff8d726435 100644
--- a/lib/cmdlib.py
+++ b/lib/cmdlib.py
@@ -12190,6 +12190,8 @@ class LUInstanceSetParams(LogicalUnit):
     private.params = new_params
     private.filled = new_filled_params
 
+    return (None, None)
+
   def CheckPrereq(self):
     """Check prerequisites.