### Question:
ContainerAttribute { public void clearSet(T key) { Preconditions.checkNotNull(key); if (attributeMap.containsKey(key)) { attributeMap.get(key).clear(); } else { if (LOG.isDebugEnabled()) { LOG.debug("key: {} does not exist in the attributeMap", 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 testClearSet() throws SCMException { List<String> keyslist = Arrays.asList("Key1", "Key2", "Key3"); ContainerAttribute<String> containerAttribute = new ContainerAttribute<>(); for (String k : keyslist) { for (int x = 1; x < 101; x++) { containerAttribute.insert(k, new ContainerID(x)); } } for (String k : keyslist) { Assert.assertEquals(100, containerAttribute.getCollection(k).size()); } containerAttribute.clearSet("Key1"); Assert.assertEquals(0, containerAttribute.getCollection("Key1").size()); }