this.onBoth = unmodifiableMap(onBoth);
      this.differences = unmodifiableMap(differences);
    }

    @Override
    public boolean areEqual() {
      return onlyOnLeft.isEmpty() && onlyOnRight.isEmpty() && differences.isEmpty();
    }

    @Override
    public Map<K, V> entriesOnlyOnLeft() {
      return onlyOnLeft;
    }

    @Override
    public Map<K, V> entriesOnlyOnRight() {