public function getChecks($limit = NULL, $offset = NULL) {
    $parameters = array();
    if (!empty($limit)) {
      $parameters['limit'] = $limit;
      if (!empty($offset)) {
        $parameters['offset'] = $offset;
      }
    }
    $data = $this->request('GET', 'checks', $parameters);
    return $data->checks;
  }