code: def load(self):
          
          if self.__loaded:
              return False
          
          self.__loaded = True
          self.setChildIndicatorPolicy(self.DontShowIndicatorWhenChildless)
          
          # loads the children for this widget
          tree = self.treeWidget()
          if tree.groupBy():
              grps = self.childRecords().grouped(tree.groupBy())
              for grp, records in grps.items():
                  tree.createGroupItem(grp, records, self)
          else:
              for record in self.childRecords():
                  tree.createRecordItem(record, self)
          
          return True
docs: Loads the children for this record item.
          
          :return     <bool> | changed