This is a very old topic and the thing that I was doing when I wrote this is no longer possible.
It looks like I added that function to the script that was importing the users. If that’s something that you want to happen for some reason, then you likely need a plugin to do it. Describe what’s happening that’s creating the staged users that you don’t want to receive email; you’ll likely need to update whatever it is that’s doing that to run a script like the one I included. If you need a custom plugin to do that, you can post in Marketplace or contact me directly.