public function addPage() {
    $build = [
      '#theme' => 'sku_add_list',
      '#cache' => [
        'tags' => $this->entityManager()->getDefinition('acm_sku_type')->getListCacheTags(),
      ],
    ];

    $content = [];

    foreach ($this->entityManager()->getStorage('acm_sku_type')->loadMultiple() as $type) {
      $content[$type->id()] = $type;
    }

    // Bypass the sku/add listing if only one content type is available.
    if (count($content) == 1) {
      $type = array_shift($content);
      return $this->redirect('acm_sku.sku_add', ['acm_sku_type' => $type->id()]);
    }

    $build['#content'] = $content;

    return $build;
  }