Unable to save modified AssetBundle back to data.unity3d

[xxpower]

I am currently using the following code:

raw_data = obj.assets_file.save()

out_path = os.path.join(output_dir, asset_file.name)
with open(out_path, "wb") as f:
    f.write(raw_data)

This successfully saves the modified sharedassets0.assets.

However, my source file is data.unity3d (a Unity AssetBundle), and I would like to save the changes back into the AssetBundle itself.

Does UnityPy support rebuilding and saving a modified AssetBundle (data.unity3d) instead of only exporting the modified AssetsFile?