That's the end of today's class.
もうおしまいだ。
It's all over now.
interjection
that's it; that's enough; that's all
Interjection used to declare that something is finished, enough, or settled; often said when stopping an activity or concluding a matter.
おしまい!もう遊びは終わりだよ。
That's it! Playtime is over.
おしまい、おしまい。その話はもうやめよう。
That's enough. Let's stop talking about that.