*
 * <p>Keys and values may be null. All optional multimap methods are supported, and all returned
 * views are modifiable.
 *
 * <p>The lists returned by {@link #get}, {@link #removeAll}, and {@link #replaceValues} all
 * implement {@link java.util.RandomAccess}.
 *
 * <p>This class is not threadsafe when any concurrent operations update the multimap. Concurrent

  // Inheritance is closed, and all subtypes are @DoNotCall, so this is safe to suppress.
  @SuppressWarnings("DoNotCall")
  public ImmutableCollection<V> replaceValues(K key, Iterable<? extends V> values) {
    throw new UnsupportedOperationException();
  }

  /**
   * Guaranteed to throw an exception and leave the multimap unmodified.
   *

  // Inheritance is closed, and all subtypes are @DoNotCall, so this is safe to suppress.
  @SuppressWarnings("DoNotCall")
  public ImmutableCollection<V> replaceValues(K key, Iterable<? extends V> values) {
    throw new UnsupportedOperationException();
  }

  /**
   * Guaranteed to throw an exception and leave the multimap unmodified.
   *

    }
    return collection;
  }

  // Bulk Operations

  /**
   * {@inheritDoc}
   *
   * <p>The returned collection is immutable.
   */
  @Override
  public Collection<V> replaceValues(@ParametricNullness K key, Iterable<? extends V> values) {
    Iterator<? extends V> iterator = values.iterator();
    if (!iterator.hasNext()) {
      return removeAll(key);
    }