diff --git a/util/tarfileappender.py b/util/tarfileappender.py
index a9cb9bfe9..cf0605cd3 100644
--- a/util/tarfileappender.py
+++ b/util/tarfileappender.py
@@ -18,7 +18,7 @@ class TarfileAppender(TarLayerFormat):
   def get_stream(self):
     return GzipWrap(self.get_generator())
 
-  def after_tar_layer(stream, current_layer):
+  def after_tar_layer(self, current_layer):
     pass
       
   def check_tar_info(self, tar_info):