@Override
    public boolean contains(String key) {
        repo.lock(key);
        try {
            return this.repo.containsKey(key);
        } finally {
            repo.unlock(key);
        }
    }
@Test
    public void testContains() throws Exception {
        assertFalse(repo.contains(key01));

        // ADD key and check again
        assertTrue(repo.add(key01));
        assertTrue(repo.contains(key01));

    }