【雑記】50代問題とか https://nirasensei.com/2019/12/19/%e3%80%90%e9%9b%91%e8%a8%98%e3%80%9150%e4%bb%a3%e5%95%8f%e9%a1%8c%e3%81%a8%e3%81%8b/