You don't need the signature of the class teacher to join the party. If you really need to identify your school's handwriting, you will also identify it from the person in charge of the school party organization and affix the seal of the school party organization, so you don't need the signature of the former senior high school class teacher. To join the party and investigate the situation in the school is to find the person in charge of the school party to understand the situation. This is the procedure for joining the party. Therefore, you can find a school to investigate, but the original class teacher signed the exemption.