@Override
  public int size() {
    return rowList.size() * columnList.size();
  }

  /**
   * Returns an unmodifiable set of all row key / column key / value triplets. Changes to the table
   * will update the returned set.
   *
   * <p>The returned set's iterator traverses the mappings with the first row key, the mappings with
   * the second row key, and so on.
   *

  @Override
  public int size() {
    return rowList.size() * columnList.size();
  }

  /**
   * Returns an unmodifiable set of all row key / column key / value triplets. Changes to the table
   * will update the returned set.
   *
   * <p>The returned set's iterator traverses the mappings with the first row key, the mappings with
   * the second row key, and so on.
   *