Are 3 Month Resignation Notices Legal

Are 3 Month Resignation Notices Legal
A: Hey Boss, I am resigning due to personal reasons and this is my resignation letter.
Q: Who will take up your position for the rest of the semester? According to our contract, you need to give a semester’s notice. Foreign teachers don’t just grow on trees.
A: But labor law has already stipulated that workers only need to provide 30 days’ written notice to terminate the employment relationship. This kind of clause is against the law, and therefore invalid.
Q: Then I won’t approve your resignation. Your resignation letter is not accepted.
A: In that case, I can exercise my unilateral right to terminate. My application has already been delivered here in person, and I will also send it to you via WeChat and email later.
Q: How did you know all about your labour law rights?
A: I watched Edgar’s videos!