code: @Override
    public ImmutableListMultimap<V, K> inverse() {
      ImmutableListMultimap<V, K> result = inverse;
      return (result == null) ? (inverse = invert()) : result;
    }
docs: {@inheritDoc}
  
  <p>Because an inverse of a list multimap can contain multiple pairs with the same key and
  value, this method returns an {@code ImmutableListMultimap} rather than the {@code
  ImmutableMultimap} specified in the {@code ImmutableMultimap} class.
  
  @since 11.0