def update_following_events(calendar_event, pre_save, post_save)
    following_event = @calendar.terms_and_holidays.find_by(start_date: calendar_event.end_date_was + 1.day)
    if following_event
      callback = calendar_event.end_date > calendar_event.end_date_was ? pre_save : post_save
      new_event_start = calendar_event.end_date + 1.day