code: def populate_tree(self, master, parent, element,from_file=False):
          
  
          data = WidgetDescr(None, None)
          data.from_xml_node(element)
          cname = data.get_class()
          uniqueid = self.get_unique_id(cname, data.get_id())
          data.set_property('id', uniqueid)
  
          if cname in builder.CLASS_MAP:
              pwidget = self._insert_item(master, data,from_file=from_file)
              xpath = "./child"
              children = element.findall(xpath)
              for child in children:
                  child_object = child.find('./object')
                  cwidget = self.populate_tree(pwidget, child, child_object,from_file=from_file)
  
              return pwidget
          else:
              raise Exception('Class "{0}" not mapped'.format(cname))
docs: Reads xml nodes and populates tree item