implements Table<R, C, V> {

  @Override
  public boolean containsRow(@Nullable Object rowKey) {
    return Maps.safeContainsKey(rowMap(), rowKey);
  }

  @Override
  public boolean containsColumn(@Nullable Object columnKey) {
    return Maps.safeContainsKey(columnMap(), columnKey);
  }

  @Override
  public Set<R> rowKeySet() {
    return rowMap().keySet();
  }

  @Override

  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);
  }

  /**

  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
   */

  /**
   * 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
   */

      synchronized (mutex) {
        return delegate().containsRow(rowKey);
      }
    }

    @Override
    public boolean containsColumn(@Nullable Object columnKey) {
      synchronized (mutex) {
        return delegate().containsColumn(columnKey);
      }
    }

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

      synchronized (mutex) {
        return delegate().containsRow(rowKey);
      }
    }

    @Override
    public boolean containsColumn(@Nullable Object columnKey) {
      synchronized (mutex) {
        return delegate().containsColumn(columnKey);
      }
    }

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