code: def get(self, identifier, default=None):
          
          split_label = (tuple(identifier.split('.'))
                         if isinstance(identifier, str) else tuple(identifier))
          if len(split_label) == 1:
              identifier = split_label[0]
              return self.__dict__.get(identifier, default)
          path_item = self
          for identifier in split_label:
              if path_item == default or path_item is None:
                  return default
              path_item = path_item.get(identifier, default)
          return path_item
docs: Get a node of the AttrTree using its path string.
  
          Args:
              identifier: Path string of the node to return
              default: Value to return if no node is found
  
          Returns:
              The indexed node of the AttrTree