protected function param($paramName)
    {
        $fallbacks = $this->getDefaultParamsNonPersistentCached();

        if ($paramName == 'content') {
            return $this->content
                ? $this->content
                : $fallbacks['content'];
        }

        if (isset($this->params[$paramName])) {
            return $this->params[$paramName];
        } elseif (isset($fallbacks[$paramName])) {
            return $fallbacks[$paramName];
        } else {
            return null;
        }
    }