通过Powershell将用户分配给IIS AppPool

I tried this code and it appears to work fine. However, i noticed if you assign the username and password to an account that does not exist the code continues without issue. In addition, if you assign an invalid account and call stop() and then start() the IIS pool indeed stops and starts!! Furthermore, when I go to InetMgr and start,stop or recylce the pool it also stops and starts without complaining!I tried this code and it appears to work fine.