SendNotification not working, 2nd argument missing or nil?

I think it's enabled now, because earlier times I tried to use it it didn't throw any error messages when I was using the wiki code (which never works), and now it has error messages. So this is the code I tried at first:

local notify = {
		Title = "Notification Title";
		Text = "This is a test notification";
		Icon = ""; 
		Duration = 5;
	}
	
	game:GetService("StarterGui"):SetCore("SendNotification", notify)

By doing this it says that SendNotification has not been registered by the CoreScripts. So I did this:

game:GetService("StarterGui"):SetCore("SendNotification", notify)

notify = {
		Title = "Notification Title";
		Text = "This is a test notification";
		Icon = "";
		Duration = 5; 
	}
	

Then when I do this, it says something about the second argument being missing or nil. Now this should be easy to fix, but there is absolutely NO information about it on the whole internet so I have no idea what the second argument is for, and what I need to put in there.