@Override
    public boolean containsKey(Object key) {
        return underlyingMap.containsKey(key);
    }
@Test
    public void testContains() {
        Map<String, Integer> underlying = createTestMap();
        TranslatedValueMapView<String, String, Integer> view =
            new TranslatedValueMapView<>(underlying, v -> v.toString());
        assertTrue(view.containsKey("foo"));
        assertTrue(view.containsKey("bar"));
        assertTrue(view.containsKey("baz"));
        assertFalse(view.containsKey("quux"));
        underlying.put("quux", 101);
        assertTrue(view.containsKey("quux"));
    }