CommentPoster::getInstance

static function getInstance(int $taskId, int $authorId): ?CommentPoster
{
	if (!$taskId)
	{
		return null;
	}

	if (!isset(static::$instances[$taskId][$authorId]))
	{
		static::$instances[$taskId][$authorId] = new static($taskId, $authorId);
	}

	return static::$instances[$taskId][$authorId];
}