/** * Promotes this function so that it returns its result on the left side of an Either. * Kleisli arrow for the Either left projection. * * @return This function promoted to return its result on the left side of an Either. */ @SuppressWarnings("unchecked") public final <C> F1W<A, Either<B, C>> eitherLeftK() { return lift(F1Functions.eitherLeftK(this)); }