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

def get(self, identifier, default=None):
        """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
        """
        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