@Override
    default <V> PartialFunction<A, V> andThen(Function<? super B, ? extends V> after) {
        AndThen pf = new AndThen<>(this, after);
        return pf;
    }
Work exactly same as scala's PartialFunction.

@param <A> argument type
@param <B> result type
indexr-common/src/main/java/io/indexr/util/function/PartialFunction.java