diff --git a/examples/customizing_dependencies/customizing_dependencies/raw_container.py b/examples/customizing_dependencies/customizing_dependencies/raw_container.py
index b8cead02a..ad6615fc8 100644
--- a/examples/customizing_dependencies/customizing_dependencies/raw_container.py
+++ b/examples/customizing_dependencies/customizing_dependencies/raw_container.py
@@ -29,6 +29,7 @@
     metadata=TaskMetadata(cache=True, cache_version="1.0"),
 )
 
+# use `ImageSpec` to copy files or directories into container `/root`
 calculate_ellipse_area_python = ContainerTask(
     name="ellipse-area-metadata-python",
     input_data_dir="/var/inputs",