@Override
    public boolean confirm(String key) {
        repo.lock(key);
        try {
            return repo.replace(key, false, true);
        } finally {
            repo.unlock(key);
        }
    }
@Test
    public void testConfirm() throws Exception {
        // ADD first key and confirm
        assertTrue(repo.add(key01));
        assertTrue(repo.confirm(key01));

        // try to confirm a key that isn't there
        assertFalse(repo.confirm(key02));
    }