Type alias IOption<A>

IOption<A>: Option<A> & {
    bind: (<B>(f: ((a: A) => Option<B>)) => IOption<B>);
    isNone: (() => boolean);
    isSome: (() => boolean);
    map: (<B>(f: ((a: A) => B)) => IOption<B>);
    unwrap: (() => null | A);
    unwrapOr: ((or: option.OrHandler<A>) => A);
}