protected function unwrapEnvelope(array $body)
  {
    if (isset($body['data']))
    {
      return $body['data'];
    }
    else if (isset($body['items']))
    {
      $items = array();
      foreach ($body['items'] as $item)
      {
        $items[] = $item;
      }

      return $items;
    }
    return $body;
  }