     end
   end
 
-  defp delete_extras(output) do
-    for target <- ["META-INF", "mimetype", "OEBPS"] do
-      File.rm_rf! "#{output}/#{target}"
-    end
-    :ok
-  end
-
   # Helper to format Erlang datetime tuple
   defp format_datetime do
     {{year, month, day}, {hour, min, sec}} = :calendar.universal_time()

    "#{date}T#{time}Z"
  end

  defp zero_pad(val, count) do
    num = Integer.to_string(val)
    :binary.copy("0", count - byte_size(num)) <> num

    epub_file
  end

  defp generate_assets(output, _config) do
    Enum.each assets, fn({pattern, dir}) ->
      output = "#{output}/#{dir}"
