code: def unlink(self):
          
          sale_line_obj = self.env['sale.order.line']
          fr_obj = self.env['folio.room.line']
          for line in self:
              if line.order_line_id:
                  sale_unlink_obj = (sale_line_obj.browse
                                     ([line.order_line_id.id]))
                  for rec in sale_unlink_obj:
                      room_obj = self.env['hotel.room'
                                          ].search([('name', '=', rec.name)])
                      if room_obj.id:
                          folio_arg = [('folio_id', '=', line.folio_id.id),
                                       ('room_id', '=', room_obj.id)]
                          folio_room_line_myobj = fr_obj.search(folio_arg)
                          if folio_room_line_myobj.id:
                              folio_room_line_myobj.unlink()
                              room_obj.write({'isroom': True,
                                              'status': 'available'})
                  sale_unlink_obj.unlink()
          return super(HotelFolioLine, self).unlink()
docs: Overrides orm unlink method.
          @param self: The object pointer
          @return: True/False.