granting file permissions in python 2.6

Question

I'm writing this basic code , now i want to give 777 to ctp directory.. what is the best way to do that

import os
import sys

print ("Checking all required directories first...")

def checkDir():
    x='/home/aspx/psharma1'
    if os.path.isdir('x/tmp/ctp'):
        print("Directory /x/tmp/ctp exists..")
    else:
        os.mkdirs("/x/tmp/ctp")