public static <K, V> MultiVersionedKeyQuery<K, V> withKey(final K key) {
        Objects.requireNonNull(key, "key cannot be null.");
        return new MultiVersionedKeyQuery<>(key, Optional.empty(), Optional.empty(), ResultOrder.ANY);
    }
@Test
    public void shouldThrowNPEWithNullKey() {
        final Exception exception = assertThrows(NullPointerException.class, () -> MultiVersionedKeyQuery.withKey(null));
        assertEquals("key cannot be null.", exception.getMessage());
    }