public Collection<V> remove(K key)
    {
        List<V> removed = data.remove(key);
        if (removed != null) {
            for (V val : removed) {
                inverse.remove(val);
            }
        }
        return removed;
    }
@Test
    public void testRemoveWrongValue()
    {
        boolean rc = map.remove(41);
        assertThat(rc, is(false));

        assertSize(1);
    }