python实现文件夹内文件合并操作

"E:/fc_user/UserOperation" 内有百十个相同结构的文件，现在需要把这些文件写入到一个新文件“UserOperation.txt”内。
具体实现代码如下所示：

import os

for filename in os.listdir("E:/fc_user/UserOperation"):

    print("E:/fc_user/UserOperation/" + filename) 
    with open("E:/fc_user/UserOperation/"+filename,encoding="utf8") as f:

        for line in f.readlines():

            with open("E:/fc_user/UserOperation/UserOperation.txt","a",encoding="utf8") as mom:

                mom.write(line)