public @Nullable K put(@ParametricNullness V value, @ParametricNullness K key) {
      return forward.putInverse(value, key, false);
    }

    @Override
    @CanIgnoreReturnValue
    public @Nullable K forcePut(@ParametricNullness V value, @ParametricNullness K key) {
      return forward.putInverse(value, key, true);
    }

    @Override
    public BiMap<K, V> inverse() {
      return forward;
    }