On windows, if a Directory/Filename has SPACE, double quotation mark should be used. For example, "R:\just a test\hello.bat" has only one line "@echo hello world", so in the dos prompt
[quote]
R:\just a test>hello.bat
hello world

R:\just a test>cd ..

R:\>set dir1="R:\just a test"

R:\>set dir2=R:\just a test

R:\>%dir1%\hello.bat
hello world

R:\>%dir2%\hello.bat
'R:\just' is not recognized as an internal or external command 
[/quote]

Then, in python (it seems to be a common problem in all(?) python version)
[quote]
dir1= os.environ.get('dir1')
print (dir1)
print (os.path.isdir(dir1))
print (os.path.isdir(dir1.replace('"', '')))

print ('*'*10)

dir2= os.environ.get('dir2')
print (dir2)
print (os.path.isdir(dir2))
print (os.path.isdir(dir2.replace('"', '')))
[/quote]
displays
[quote]
"R:\just a test"
False                  <--obviously, the double quotation marks is treated as the part of the directory name by python, so the answer is wrong
True
**********
R:\just a test
True
True
[/quote]

the patched method is simple
[quote]
if os.name=='nt':
    res=res.replace('"', '')
[/quote]
but the not simple thing is that os.py for python 3.4.3 changes a lot than os.py for python 2.7, I get lost while reading os.py for python 3.4.3 by no IDE. So I just report this issue, sorry.