How To Put Animations Into A KeyPress Function?

So I've trying to make it so when I key is pressed like F for example some code will run and an animation will play but because I don't know if ROBLOX allows you to put a function in a function I put the animation in a local script and the code in the other and it won't work. Heres the code.

    function onKeyDown(key) --Keydown function can't have Animation Function

    if key == "f" then
        a = game.Lighting.Script.Animation:Clone() --Trying to make Animation Run
    end
    end)

    mouse.KeyDown:connect(onKeyDown)