python新手遇到的问题，‘\’在windows中显示为‘\\’，报错，怎么解决?报错

#!/usr/bin/python
#Filename:FileBackUP.py

import os
import time
source = [r'd:\temp', r'd:\"tools config"']
target_dir = 'd:\\python_tmp\\' + time.strftime('%Y%m%d')

target_filename = target_dir + '\\' + time.strftime('%H%M%S') + '.zip'
zip_command = r'c:\"program files"\7-zip\7z.exe a %s %s' %(target_filename, " ".join(source))
if not os.path.exists(target_dir):
    os.mkdir(target_dir)
    print 'Successfully created directory', target_dir

if os.system(zip_command) == 0:
    print 'Successful backup to ',target_filename
else:
    print 'Backup Failed'

上面的代码执行后，提示

C:\Users\leo>python C:\Users\leo\Desktop\test.py
Traceback (most recent call last):
  File "C:\Users\leo\Desktop\test.py", line 12, in <module>
    os.mkdir(target_dir)
WindowsError: [Error 3] : 'd:\\python_tmp\\20170213'

这个问题怎么解决，请大神帮忙，谢谢