Not a function?

ison = false

humanname = script.Parent.Parent.Parent.Parent.Parent.Name
veh = game.Workspace:FindFirstChild(humanname).PoliceTahoe

function on()
ison = true

local children = veh.PT:GetChildren()
for i=1, #children do
if children[i].Name == "Light" then
children[i].Material = ("Neon")

local children = veh.PT:GetChildren()
for i=1, #children do
if children[i].Name == "NightLight" then
children[i].SpotLight.Enabled = true


function off()
ison = false

local children = veh.PT:GetChildren()
for i=1, #children do
if children[i].Name == "Light" then
children[i].Material = ("Plastic")

local children = veh.PT:GetChildren()
for i=1, #children do
if children[i].Name == "NightLight" then
children[i].SpotLight.Enabled = false

function toggle()
if ison == true then off() else on() end
end


                                    end
                                end
                            end
                        end
                    end
                end
            end
        end
    end
end

script.Parent.MouseButton1Click:connect(toggle) 

So above is my script, and when I run it, the output tells me that "toggle" is not a function. How do I fix this?