Lock current working directory in subprocess? or make cwd as home directory

Question

simply I am using windows 10 operating system and run code in python as

main.py

cmd = "python example.py"
sp = subprocess.Popen(cmd, shell=True, stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.PIPE, universal_newlines=True, cwd="/home", env=new_env)

so cwd is now C:/home but using os.chdir() I am able to change directory to D: or like C:/User/Desktop etc, externally using example.py.

Now, I would like to lock the directory to /home so, if any code run through example.py then the main directory for the code run in example.py will be /home and the directory is not be able to change from /home any other directory.