// requireNonNull is safe because of the containsColumn check.
      return containsColumn(key) ? column((C) requireNonNull(key)) : null;
    }

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

    @Override
    public @Nullable Map<R, V> remove(@Nullable Object key) {
      return containsColumn(key) ? removeColumn(key) : null;
    }

      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) {

  public boolean contains(@Nullable Object rowKey, @Nullable Object columnKey) {
    return containsRow(rowKey) && containsColumn(columnKey);
  }

  /**
   * Returns {@code true} if the provided column key is among the column keys provided when the
   * table was constructed.
   */
  @Override
  public boolean containsColumn(@Nullable Object columnKey) {
    return columnKeyToIndex.containsKey(columnKey);
  }

  /**

  /**
   * Returns {@code true} if the table contains a mapping with the specified column.
   *
   * @param columnKey key of column to search for
   */
  boolean containsColumn(@CompatibleWith("C") @Nullable Object columnKey);

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