How to trigger functions in game

[Lyeeroy]

Hi, have simple question..

Have a code with functions like this:

local version = 0.8
 
print("func " .. version .. " loaded")
 
function func_OnEvent(self, event)
    --some code
end
 
function MsgTop(string)
    --some code
end
 
function MsgChat(string)
    --some code
end

How do I call _OnEvent in game? I cant get it. Is this via XML? Or should I just call it on top of the code by:

func_OnEvent()

It seems weird.