docs: def additional_assets(context: Context):
      """
      Collects assets from GOV.UK frontend toolkit
      """
      rsync_flags = '-avz' if context.verbosity == 2 else '-az'
      for path in context.app.additional_asset_paths:
          context.shell('rsync %s %s %s/' % (rsync_flags, path, context.app.asset_build_path))