parent is not a valid member of Model? plzz help

It says "parent is not a valid member of Model"

    for _, object in pairs(game.ServerStorage:GetChildren()) do
        local CarCopy = object:clone()
        CarCopy.parent = game.Workspace
        CarCopy:MakeJoints()
    end

I want to make the CarCopy to go in to the Workspace from my ServerStorage but it is not doing it here is all the scripts in that one script

local RespawnCarsBlock = game.Workspace.RestartCars


function RespawnCars()
    print("Cars is respawning!")

    for _, object in pairs(game.Workspace:GetChildren()) do
        print(object.name)
        if object.name == "Motorcycle" then
            print("this is a Motorcycle we need to destroy it!")
            object:destroy()
        end
    end

    for _, object in pairs(game.ServerStorage:GetChildren()) do
        local CarCopy = object:clone()
        CarCopy.parent = game.Workspace
        CarCopy:MakeJoints()
    end




end


RespawnCarsBlock.Touched:connect(RespawnCars())