diff --git a/build/gen.py b/build/gen.py
index 6f3652e..d1c649c 100755
--- a/build/gen.py
+++ b/build/gen.py
@@ -101,7 +101,7 @@
     return self._platform == 'zos'
 
   def is_serenity(self):
-    return self_.platform == 'serenity'
+    return self._platform == 'serenity'
 
 class ArgumentsList:
   """Helper class to accumulate ArgumentParser argument definitions