请问大神怎样用python批量读取文件夹下的文件？

import os
def search(s, path=os.path.abspath('.')):
    for z in os.listdir(path):
        if os.path.isdir(path + os.path.sep + z):
            print('Currnet:', path)
            path2 = os.path.join(path, z)
            print('future:', path2)
            search(s, path2)
        elif os.path.isfile(path + os.path.sep + z):
            if s in z:
                print(os.path.join(path, z))
                with open(path + os.path.sep + z, 'r') as fr:
                    with open('save.txt', 'a') as fw:
                        fw.write(path + '\t' + fr.read())
search('csv', '.')