使用Python将文件列表添加到zip文件中

我想编写一个脚本，将所有“ .py”文件添加到一个zip文件中。

这是我所拥有的：

import zipfile
import os

working_folder = 'C:\\Python27\\'

files = os.listdir(working_folder)

files_py = []

for f in files:
    if f[-2:] == 'py':
        fff = working_folder + f
        files_py.append(fff)

ZipFile = zipfile.ZipFile("zip testing.zip", "w" )

for a in files_py:
    ZipFile.write(a, zipfile.ZIP_DEFLATED)

但是它给出了一个错误：

Traceback (most recent call last):
  File "C:\Python27\working.py", line 19, in <module>
    ZipFile.write(str(a), zipfile.ZIP_DEFLATED)
  File "C:\Python27\lib\zipfile.py", line 1121, in write
    arcname = os.path.normpath(os.path.splitdrive(arcname)[1])
  File "C:\Python27\lib\ntpath.py", line 125, in splitdrive
    if p[1:2] == ':':
TypeError: 'int' object has no attribute '__getitem__'

因此似乎给定的文件名不正确。