@Override
    public boolean isValid(K key, UUID ticket) {
        if (timeouts.containsKey(key)) {
            Timeout<K> timeout = timeouts.get(key);

            return timeout.getTicket().equals(ticket);
        } else {
            return false;
        }
    }
@Test
    void testIsValidInitiallyReturnsFalse() {
        final DefaultTimerService<AllocationID> timerService = createAndStartTimerService();

        assertThat(timerService.isValid(new AllocationID(), UUID.randomUUID())).isFalse();
    }