如何通过扩展名'filename_ext'.txt并递归地将文件附加到文件夹中的所有文件，并将它们转换回原始扩展名

import os

def rename_files(folder_path, original_ext, new_ext):
    for root, dirs, files in os.walk(folder_path):
        for file in files:
            file_path = os.path.join(root, file)
            file_name, ext = os.path.splitext(file)
            if ext == '.' + original_ext:
                new_file_name = file_name + '.' + new_ext
                new_file_path = os.path.join(root, new_file_name)
                os.rename(file_path, new_file_path)

        for dir in dirs:
            rename_files(os.path.join(root, dir), original_ext, new_ext)

# 调用示例
folder_path = '/path/to/folder'  # 文件夹路径
original_ext = 'txt'  # 原始扩展名
new_ext = 'txt'  # 新的扩展名
rename_files(folder_path, original_ext, new_ext)