code: def inventory_text(self):
          
          if self._inventory_text is None:
              self.chain.connection.log("Collecting inventory information")
              self._inventory_text = self.driver.get_inventory_text()
              if self._inventory_text:
                  self.chain.connection.log("Inventory info collected")
              else:
                  self.chain.connection.log("Inventory info not collected")
          return self._inventory_text
docs: Return inventory information and collect if not available.