LookupFilter for image save is not working

[Mubin-khan]

effect = LookupFilter() effect.lookupImage = PictureInput(image: UIImage(named: "effect1")!) effect.intensity = 1

let filteredImage = originalImage?.filterWithOperation(effect)

when i'm trying to apply lookup filter getting error "Unexpectedly found nil while unwrapping an Optional value" but in renderView for displaying image it works totally fine. could anyone help please ??