Thank you very much Abishek!
Had some trouble finding the API_KEY and USER_KEY from the push over for notifications, got some help from my friend and was able to work it out. The homepage of pushover shows the USER_KEY after login (same in the app) and the API_KEY needs to be created by clicking (Create an Application/API Token).
This script is running fine and hopefully I would get a notification when the slot is available. Thanks again.