- zip4Opt<T>(x): (<A>(a) => (<B>(b) => (<C>(c) => Opt<[T, A, B, C]>)))
 Returns (<A>(a) => (<B>(b) => (<C>(c) => Opt<[T, A, B, C]>)))
- <A>(a): (<B>(b) => (<C>(c) => Opt<[T, A, B, C]>))
 Returns (<B>(b) => (<C>(c) => Opt<[T, A, B, C]>))
- <B>(b): (<C>(c) => Opt<[T, A, B, C]>)
 Returns (<C>(c) => Opt<[T, A, B, C]>)
- <C>(c): Opt<[T, A, B, C]>
 Returns Opt<[T, A, B, C]>
See
Opt.zip4