diff --git a/src/fairseq2/utils/dataclass.py b/src/fairseq2/utils/dataclass.py
index cae1deabb..85ac3cefd 100644
--- a/src/fairseq2/utils/dataclass.py
+++ b/src/fairseq2/utils/dataclass.py
@@ -17,7 +17,7 @@
 
 class _EmptyType:
     def __reduce__(self) -> str:
-        return _EmptyType.__name__
+        return "EMPTY"
 
     def __copy__(self) -> Self:
         return self