protected function _callApiPreparationsGet(
    $httpmethod, $url, $params, $app_only_auth
  ) {
    return [
      $app_only_auth                ? null : $this->_sign($httpmethod, $url, $params),
      json_encode($params) === '[]' ? $url : $url . '?' . http_build_query($params)
    ];
  }