How do I fix "_____ is not a valid member of Model "____" "?

local XStuds = 1
local YStuds = 0.5
local ZStuds = -170

local function Stage(Value)
	local Value = game.Workspace.Stage.Value:Clone() -- This is the line of code that breaks
	Value.Parent = game.Workspace
	Value.Position = Vector3.new(XStuds, YStuds, ZStuds)
	XStuds = XStuds + 58
	YStuds = YStuds + 58
	ZStuds = ZStuds + 58
	print(Value)
end

Stage(Part1)
Stage(Part2)
Stage(Part3)
Stage(Part4)
Stage(Part5)
Stage(Part6)

wait(3)

while wait(15) do
	Part1.Parent = game.Workspace
	Part1.Position = Vector3.new(0, 0, 0)
	studs = studs + 58
	Part2.Parent = game.Workspace
	Part2.Position = Vector3.new(0, 0, 0)
	studs = studs + 58
end