In Drupal 8,  rendering Tables is still a lot like Drupal 7.  You build out  multi-dimensional arrays of rows and columns in PHP that Drupal transforms into a `<tr>` and `<td>`s respectively.  There is still this confusing Drupalism known as `'data'` that lets you add render array elements as cell data (not to be confused with data attributes).

I've been given a site where the developer chose to use 'data' to render the contents of the cell, but I cannot figure out how to add a class to the `<td>` around the data.

I've read the source code and documentation for [Table.php][1] and I'm aware of the new `#wrapper_attributes`  but I cannot crack this.

I've tried at least four ways to add the class, and none work.

    $table['row-' . $row_id] = [

      // Option 1: Class appears on <tr> tag
      '#attributes' => [
        'class' => ['option-1-row-attributes'],
        'id' => 'row-' . $row_id,
        'no_striping' => TRUE,
      ],

      // Option 2: Class appears on <td> tag of first column. 
      'item' => [
        '#markup' => $row['my_item']->label(),
        '#wrapper_attributes' => [   
          'class' => ['option-2-markup-wrapper-attributes'],
        ],
      ],

      // In the following section, the only item that works is
      // the class on the <a> tag.
      'edit_operation' => [
        'data' => [
          '#type' => 'link',
          '#url' => Url::fromRoute('my_module.my_route', ['item' => $row_id]),
          '#title' => $this->t('Edit'),
          '#attributes' => [
            // Option 3: Class appears on the anchor tag
            'class' => ['use-ajax', 'option-3-link-attributes'],
            'data-dialog-type' => 'modal',
            'data-dialog-options' => Json::encode([
              'width' => 700,
            ]),
          ],
          // Option 4: Has no effect.
          '#wrapper_attributes' => [
            'class' => ['option-4-data-wrapper-attributes'],
          ],
        ],
        // Option 5: Update: This appears to be the correct solution! 
        // Class appears on the <td>.
        '#wrapper_attributes' => [
          'class' => ['option-5-wrapper-attributes'],
        ],
        // Option 6: Has no effect.
        '#attributes' => [
          'class' => ['option-6-attributes'],
        ],
        // Option 7: Has no effect.
        'class' => ['option-7-attributes'],
      ],
    ];

  [1]: https://api.drupal.org/api/drupal/core!lib!Drupal!Core!Render!Element!Table.php/class/Table/8.2.x