code: def reservation_reminder_24hrs(self):
          
          now_str = time.strftime(dt)
          now_date = datetime.strptime(now_str, dt)
          ir_model_data = self.env['ir.model.data']
          template_id = (ir_model_data.get_object_reference
                         ('hotel_reservation',
                          'mail_template_reservation_reminder_24hrs')[1])
          template_rec = self.env['mail.template'].browse(template_id)
          for reserv_rec in self.search([]):
              checkin_date = (datetime.strptime(reserv_rec.checkin, dt))
              difference = relativedelta(now_date, checkin_date)
              if(difference.days == -1 and reserv_rec.partner_id.email and
                 reserv_rec.state == 'confirm'):
                  template_rec.send_mail(reserv_rec.id, force_send=True)
          return True
docs: This method is for scheduler
          every 1day scheduler will call this method to
          find all tomorrow's reservations.
          ----------------------------------------------
          @param self: The object pointer
          @return: send a mail