### Question:
ContainerAttribute { public boolean hasKey(T key) { Preconditions.checkNotNull(key); return this.attributeMap.containsKey(key); } ContainerAttribute(Map<T, NavigableSet<ContainerID>> attributeMap);  ContainerAttribute(); boolean insert(T key, ContainerID value); boolean hasKey(T key); boolean hasContainerID(T key, ContainerID id); boolean hasContainerID(T key, int id); void clearSet(T key); boolean remove(T key, ContainerID value); NavigableSet<ContainerID> getCollection(T key); void update(T currentKey, T newKey, ContainerID value);  }### Answer:
@Test public void testHasKey() throws SCMException { ContainerAttribute<Integer> containerAttribute = new ContainerAttribute<>(); for (int x = 1; x < 42; x++) { containerAttribute.insert(1, new ContainerID(x)); } Assert.assertTrue(containerAttribute.hasKey(1)); for (int x = 1; x < 42; x++) { Assert.assertTrue(containerAttribute.hasContainerID(1, x)); } Assert.assertFalse(containerAttribute.hasContainerID(1, new ContainerID(42))); }