List Available Drive Letters In Python

I'm using Python version 3.3.2

import string
from ctypes import windll

def get_drives():
    drives = []
    bitmask = windll.kernel32.GetLogicalDrives()
    for letter in string.ascii_uppercase:
        if bitmask & 1:
            drives.append(letter)
        bitmask >>= 1

    return drives

if __name__ == '__main__':
    print (get_drives())     # On my PC, this prints ['C', 'D', 'W', 'X', 'Y', 'Z']