private static function getRandomWinner(&$data, &$alreadyWinners) {
    // Randomize array.
    shuffle($data);

    $memberCampaignItem = array_shift($data);

    if (!in_array($memberCampaignItem['member_campaign'], $alreadyWinners)) {
      $alreadyWinners[] = $memberCampaignItem['member_campaign'];
      return $memberCampaignItem;
    }
    else {
      if (!empty($data)) {
        return self::getRandomWinner($data, $alreadyWinners);
      }
    }
  }