def cbz(dir)
      Mangdown::CBZ.all(dir)
    rescue StandardError => error
      raise Mangdown::Error, "Failed to package #{dir}: #{error.message}"
    end
def cbz(dir)
      Mangdown::CBZ.all(dir)
    rescue StandardError => error
      raise Mangdown::Error, "Failed to package #{dir}: #{error.message}"
    end
cbz all subdirectories in a directory