Here's my code:

maplist = game.ServerStorage.Maps:GetChildren()
mapref = GetMap(maplist)
map = mapref:Clone()

The GetMap function looks like this:

function GetMap(tbl)
	local returntbl={}
	if tbl[1]~=nil then
		for i=1,#tbl do
			table.insert(returntbl,math.random(1,#returntbl+1),tbl[i])
		end
	end
	return returntbl
end

Why is studio telling me that my error is "attempt to call method 'Clone' (a nil value)"? How do I fix this?