Background: I am a junior undergrad math major in India, and I am taking a graduate-level math course this semester for which attendance is mandatory. This is the last week of instruction (i.e., Friday is the last working day of the semester), and it is immediately followed by endterm exams (starting Saturday itself). One of my professors wishes to take certain classes and meet for presentations (by students), after dinner time. This is quite unusual, keeping in mind that the official university timetable does not have any lecture slots after 20:00. Regardless, I do not mind it, as long as the classes/presentations do not run for too long. We plan to meet at 20:00/20:30, and it's no trouble if the classes end by 22:30, or even 23:00, in the worst case. I am an early sleeper, I have faced certain sleep issues in the past, and I strongly do not prefer late night classes, i.e., ones that may run beyond 22:30 for example.
Question: How can I communicate my concerns and politely request the professor to perhaps ensure (i) some upper bound on the classes/presentation time, (ii) that I do not have to stay too late, or (iii) find some other time, earlier in the day? It seems like a reasonable ask since the class timings are abnormal, and later than usual. I would prefer not to play around much with my sleep schedule, especially since finals are starting soon.
Update: Thank you everyone for your advice! I voiced my concerns firmly to the instructor and requested a different, possibly earlier time slot. With consent from other students in the course, we were able to figure out a time in the afternoon/early evening for the final presentations! It's a win.