Lua Add sleep function

[Nekiro]

Hello, how to add sleep function to this script:

function onStepIn(creature, item, position, fromPosition)
    local player = creature:getPlayer()
        player:say('TEST MESSAGE.', TALKTYPE_MONSTER_SAY)
    end

I want to execute this lua only once on every player

 

[narko]

Just an example, I made on my cellphone.

local once = 30000
if player:getStorageValue(once) =~ 1 then
     player:setStorageValue(once, 1)
     ----- function that will be executed once