public static function attributes_for($modelName, $recordCount = 1, $callback = null)
    {
        $instance = self::getInstance();
        $instance->factory = $instance->factory($modelName);
        $definition = $instance->definition($recordCount, $callback);
        $recordCount = $instance->recordCount($recordCount);
        return $instance->factory->attributes_for($recordCount, $definition);
    }