python中如何遍历目录树

import os

for folderName, subfolders, filenames in os.walk('C:\\delicious'):

    print('当前目录(文件夹) folder 是 ' + folderName)

        for subfolder in subfolders:

            print('目录下子文件夹 subflder 是 ' + folderName + ': ' + subfolder)

        for filename in filenames:

            print('目录下文件 file 是 ' + folderName + ': '+ filename)

        print('')