public static function deleteAllMembersProcessBatch(&$context) {
    if (empty($context['sandbox'])) {
      $memberIds = \Drupal::entityQuery('openy_campaign_member')->execute();
      $memberCampaignIds = \Drupal::entityQuery('openy_campaign_member_campaign')->execute();

      $context['sandbox']['progress'] = 0;

      $context['sandbox']['members'] = array_values($memberIds);
      $context['sandbox']['member_campaigns'] = array_values($memberCampaignIds);
      $context['sandbox']['max'] = count($memberCampaignIds);
    }
    // Get Member and MemberCampaign ids.
    $memberId = $context['sandbox']['members'][$context['sandbox']['progress']];
    $memberCampaignId = $context['sandbox']['member_campaigns'][$context['sandbox']['progress']];

    // Get Member entity manager.
    $memberStorage = \Drupal::entityTypeManager()
      ->getStorage('openy_campaign_member');
    // Get MemberCampaign entity manager.
    $memberCampaignStorage = \Drupal::entityTypeManager()
      ->getStorage('openy_campaign_member_campaign');

    // Delete Member entity.
    $entities = $memberStorage->loadMultiple([$memberId]);
    $memberStorage->delete($entities);
    // Delete MemberCampaign entity.
    $entities = $memberCampaignStorage->loadMultiple([$memberCampaignId]);
    $memberCampaignStorage->delete($entities);

    // Save results.
    $context['results'][] = $memberId;
    $context['sandbox']['progress']++;
    if ($context['sandbox']['progress'] != $context['sandbox']['max']) {
      $context['finished'] = $context['sandbox']['progress'] / $context['sandbox']['max'];
    }
  }