code: def folio_room_lines(self):
          '''
          This method is used to validate the room_lines.
          ------------------------------------------------
          @param self: object pointer
          @return: raise warning depending on the validation
          '''
          folio_rooms = []
          for room in self[0].room_lines:
              if room.product_id.id in folio_rooms:
                  raise ValidationError(_('You Cannot Take Same Room Twice'))
              folio_rooms.append(room.product_id.idf folio_room_lines(self):
          '''
          This method is used to validate the room_lines.
          ------------------------------------------------
          @param self: object pointer
          @return: raise warning depending on the validation
          '''
          folio_rooms = []
          for room in self[0].room_lines:
              if room.product_id.id in folio_rooms:
                  raise ValidationError(_('You Cannot Take Same Room Twice'))
              folio_rooms.append(room.product_id.id)
docs: This method is used to validate the room_lines.
          ------------------------------------------------
          @param self: object pointer
          @return: raise warning depending on the validation