code: def create(self, vals):
          
          if not vals:
              vals = {}
          vals['reservation_no'] = self.env['ir.sequence'].\
              next_by_code('hotel.reservation') or 'New'
          return super(HotelReservation, self).create(vals)
docs: Overrides orm create method.
          @param self: The object pointer
          @param vals: dictionary of fields value.