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

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

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

  @Override
  public void testContainsColumn() {
    table = create("foo", 1, 'a', "bar", 1, 'b', "foo", 3, 'c');
    assertTrue(table.containsColumn(1));
    assertTrue(table.containsColumn(3));
    assertTrue(table.containsColumn(2));
    assertFalse(table.containsColumn(-1));
    assertFalse(table.containsColumn(null));
  }

  @Override
  public void testContainsValue() {

  @Override
  public void testContainsColumn() {
    table = create("foo", 1, 'a', "bar", 1, 'b', "foo", 3, 'c');
    assertTrue(table.containsColumn(1));
    assertTrue(table.containsColumn(3));
    assertTrue(table.containsColumn(2));
    assertFalse(table.containsColumn(-1));
    assertFalse(table.containsColumn(null));
  }

  @Override
  public void testContainsValue() {

    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(@CheckForNull Object columnKey) {
    return columnKeyToIndex.containsKey(columnKey);
  }

  /**

      return original.contains(columnKey, rowKey);
    }

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

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

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

    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(@CheckForNull 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") @CheckForNull Object columnKey);

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