*/
    public static <KEY, VALUE> Maps<KEY, VALUE> hashMap(final KEY key, final VALUE value) {
        return new Maps<>(new HashMap<KEY, VALUE>()).$(key, value);
    }

    /**
     * Returns a {@literal Maps} for constructing a {@link Hashtable} with the specified key and value.
     *
     * @param <KEY> the key type of the <code>Map</code>

        if (valueItr == null) {
          valueIterators.put(key, valueItr = sampleValuesIterator());
        }
        entries[i] = mapEntry(key, valueItr.next());
      }
      return multimapGenerator.create((Object[]) entries).keys();
    }

    private Iterator<V> sampleValuesIterator() {
      return ((TestMultimapGenerator<K, V, M>) multimapGenerator.getInnerGenerator())
          .sampleValues()

  interface Construction<T> {
    @CanIgnoreReturnValue
    T create(List<?> keys);

    static Construction<Map<Object, Object>> mapFromKeys(
        Supplier<Map<Object, Object>> mutableSupplier) {
      return keys -> {
        Map<Object, Object> map = mutableSupplier.get();
        for (Object key : keys) {
          map.put(key, new Object());
        }
        return map;
      };
    }

 * Null row keys, columns keys, and values are not supported.
 *
 * <p>Lookups by row key are often faster than lookups by column key, because the data is stored in
 * a {@code Map<R, Map<C, V>>}. A method call like {@code column(columnKey).get(rowKey)} still runs
 * quickly, since the row key is provided. However, {@code column(columnKey).size()} takes longer,
 * since an iteration across all row keys occurs.
 *

    for (K key : multimap().keySet()) {
      assertTrue(multimap().asMap().get(key) instanceof List);
    }
  }

  @MapFeature.Require(SUPPORTS_REMOVE)
  public void testAsMapRemoveImplementsList() {
    List<K> keys = new ArrayList<>(multimap().keySet());
    for (K key : keys) {
      resetCollection();
      assertTrue(multimap().asMap().remove(key) instanceof List);
    }
  }

    for (K key : multimap().keySet()) {
      assertTrue(multimap().asMap().get(key) instanceof List);
    }
  }

  @MapFeature.Require(SUPPORTS_REMOVE)
  public void testAsMapRemoveImplementsList() {
    List<K> keys = new ArrayList<>(multimap().keySet());
    for (K key : keys) {
      resetCollection();
      assertTrue(multimap().asMap().remove(key) instanceof List);
    }
  }

   * key. When a key-value pair is added to a multimap that didn't previously
   * contain any values for that key, a new collection generated by
   * createCollection is added to the map. That same collection instance
   * remains in the map as long as the multimap has any values for the key. If
   * all values for the key are removed, the key and collection are removed
   * from the map.
   *

 * Null row keys, columns keys, and values are not supported.
 *
 * <p>Lookups by row key are often faster than lookups by column key, because the data is stored in
 * a {@code Map<R, Map<C, V>>}. A method call like {@code column(columnKey).get(rowKey)} still runs
 * quickly, since the row key is provided. However, {@code column(columnKey).size()} takes longer,
 * since an iteration across all row keys occurs.
 *

  @Override
  public boolean containsKey(@Nullable Object key) {
    if (unfiltered.containsKey(key)) {
      @SuppressWarnings("unchecked") // k is equal to a K, if not one itself
      K k = (K) key;
      return keyPredicate.apply(k);
    }
    return false;
  }

  @Override
  public Collection<V> removeAll(@Nullable Object key) {
    return containsKey(key) ? unfiltered.removeAll(key) : unmodifiableEmptyCollection();
  }

  @Override
  public boolean containsKey(@Nullable Object key) {
    if (unfiltered.containsKey(key)) {
      @SuppressWarnings("unchecked") // k is equal to a K, if not one itself
      K k = (K) key;
      return keyPredicate.apply(k);
    }
    return false;
  }

  @Override
  public Collection<V> removeAll(@Nullable Object key) {
    return containsKey(key) ? unfiltered.removeAll(key) : unmodifiableEmptyCollection();
  }