@Override
    public int addFirstIfExists(V... elements) {
        return get(addFirstIfExistsAsync(elements));
    }
@Test
    public void testAddIfExists() {
        RDeque<Integer> deque1 = redisson.getDeque("deque1");
        deque1.add(1);
        deque1.add(2);
        deque1.add(3);

        deque1.addFirstIfExists(4, 5);

        assertThat(deque1).containsExactly(5, 4, 1, 2, 3);
    }