code: final public function getFromListAt($fieldName, $index, $default = null)
      {
          $index = (int) $index;
          if (empty($this->data[$fieldName])
              || !is_array($this->data[$fieldName])
              || !isset($this->data[$fieldName][$index])
          ) {
              return $default;
          }
          return $this->data[$fieldName][$index];
      }
docs: {@inheritdoc}