public boolean containsKey(@Nullable Object key) {
      return containsRow(key);
    }

    // performing cast only when key is in backing map and has the correct type
    @SuppressWarnings("unchecked")
    @Override
    public @Nullable Map<C, V> get(@Nullable Object key) {
      // requireNonNull is safe because of the containsRow check.
      return containsRow(key) ? row((R) requireNonNull(key)) : null;
    }

    public boolean containsKey(@Nullable Object key) {
      return containsRow(key);
    }

    // performing cast only when key is in backing map and has the correct type
    @SuppressWarnings("unchecked")
    @Override
    public @Nullable Map<C, V> get(@Nullable Object key) {
      // requireNonNull is safe because of the containsRow check.
      return containsRow(key) ? row((R) requireNonNull(key)) : null;
    }

    /*
     * TODO(jlevy): Support only one of rowKey / columnKey being empty? If we
     * do, when columnKeys is empty but rowKeys isn't, rowKeyList() can contain
     * elements but rowKeySet() will be empty and containsRow() won't
     * acknowledge them.
     */
    rowKeyToIndex = Maps.indexMap(rowList);
    columnKeyToIndex = Maps.indexMap(columnList);

    @SuppressWarnings("unchecked")

    /*
     * TODO(jlevy): Support only one of rowKey / columnKey being empty? If we
     * do, when columnKeys is empty but rowKeys isn't, rowKeyList() can contain
     * elements but rowKeySet() will be empty and containsRow() won't
     * acknowledge them.
     */
    rowKeyToIndex = Maps.indexMap(rowList);
    columnKeyToIndex = Maps.indexMap(columnList);

    @SuppressWarnings("unchecked")

      @CompatibleWith("C") @Nullable Object columnKey);

  /**
   * Returns {@code true} if the table contains a mapping with the specified row key.
   *
   * @param rowKey key of row to search for
   */
  boolean containsRow(@CompatibleWith("R") @Nullable Object rowKey);

  /**
   * Returns {@code true} if the table contains a mapping with the specified column.
   *
   * @param columnKey key of column to search for
   */

      @CompatibleWith("C") @Nullable Object columnKey);

  /**
   * Returns {@code true} if the table contains a mapping with the specified row key.
   *
   * @param rowKey key of row to search for
   */
  boolean containsRow(@CompatibleWith("R") @Nullable Object rowKey);

  /**
   * Returns {@code true} if the table contains a mapping with the specified column.
   *
   * @param columnKey key of column to search for
   */

      return original.contains(columnKey, rowKey);
    }

    @Override
    public boolean containsColumn(@Nullable Object columnKey) {
      return original.containsRow(columnKey);
    }

    @Override
    public boolean containsRow(@Nullable Object rowKey) {
      return original.containsColumn(rowKey);
    }

    @Override
    public boolean containsValue(@Nullable Object value) {

      return original.contains(columnKey, rowKey);
    }

    @Override
    public boolean containsColumn(@Nullable Object columnKey) {
      return original.containsRow(columnKey);
    }

    @Override
    public boolean containsRow(@Nullable Object rowKey) {
      return original.containsColumn(rowKey);
    }

    @Override
    public boolean containsValue(@Nullable Object value) {