### Question:
ArrayListMultimap implements Multimap<K, V> { @Override public boolean put(final K key, final V value) { return map.computeIfAbsent(key, k -> new ArrayList<>()).add(value); } private  ArrayListMultimap(); static ArrayListMultimap<K, V> create(); @Override boolean put(final K key, final V value); @Override Collection<V> get(final K key); @Override Collection<V> values(); @Override Multiset<K> keys(); @Override boolean equals(Object o); @Override int hashCode();  }### Answer:
@Test public void put() { final var given = ArrayListMultimap.create(); assertTrue(given.put("key1", "item1")); assertTrue(given.put("key1", "item1")); assertTrue(given.put("key1", "item2")); }