Loads the children for this record item.
        
        :return     <bool> | changed

def load(self):
        """
        Loads the children for this record item.
        
        :return     <bool> | changed
        """
        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