Bad Argument @ getElementParent

[Ryan2233]

function detectHit()
if getElementType(markerBlip)=="vehicle" then 
outputChatBox("Get out of that vehicle",markerBlip,255,0,0)
else
outputChatBox("Get out of that vehicle",markerBlip,255,0,0)
end
end

function devMarker()

local deliveryMarker = createMarker(-2300.9340820313, -1649.5125732422, 483.56658935547, "checkpoint")

local markerBlip = createBlipAttachedTo(deliveryMarker, 23)

addEventHandler("onMarkerHit", markerBlip, devMarker)

end
function setupSpawns(thePlayer, command)
local x, y, z = getElementPosition(thePlayer)
local helicopter = createVehicle(417, 0, 0, 0)
local spawnVehicle = spawnVehicle (helicopter, x+3, y+3, z)
if spawnVehicle then exports.SANGcommands:sendMessage("A helicopter has been abandonded (R Icon). Deliver it for a good payday!", 255, 255, 255)

local heliBlip = createBlipAttachedTo(helicopter, 34)

end
end


addCommandHandler("startheli", setupSpawns)
addCommandHandler("startheli", devMarker)
setElementParent(heliBlip, helicopter)

[expected element at argument 1, got nil] ~ How to fix?

[Storm-Hanma]

Define it with hit element nor get elements by type ,you r creating markers so you will hit the markers then the function will work change line 2