How to limit number of user in ERPNEXT self hosted version?

ERPNext
1

Hey Can anyone guide me how can i put limit on total number of users of erpnext?
I have to install it for other person but want to keep limit of users lets say only 5 user and if admin try to create any other user they will get error or user will not be created

2
3

Hey after installing this app whenever I am trying to update the profile or add new domains I am getting following error.

Server Error

KeyError: ‘users’
I have checked and without this app everthing is fine but after this app the error is coming