[python] Negation in Python

I'm trying to create a directory if the path doesn't exist, but the ! (not) operator doesn't work. I'm not sure how to negate in Python... What's the correct way to do this?

if (!os.path.exists("/usr/share/sounds/blues")):
        proc = subprocess.Popen(["mkdir", "/usr/share/sounds/blues"])
        proc.wait()

try instead:

if not os.path.exists(pathName):
    do this

Combining the input from everyone else (use not, no parens, use os.mkdir) you'd get...

special_path_for_john = "/usr/share/sounds/blues"
if not os.path.exists(special_path_for_john):
    os.mkdir(special_path_for_john)

Python prefers English keywords to punctuation. Use not x, i.e. not os.path.exists(...). The same thing goes for && and || which are and and or in Python.