@classmethod
def dump_bulk(cls, parent=None, keep_ids=True):
    """
        Dumps a tree branch to a python data structure.

        :param parent:

            The node whose descendants will be dumped. The node itself will be
            included in the dump. If not given, the entire tree will be dumped.

        :param keep_ids:

            Stores the id value (primary key) of every node. Enabled by
            default.

        :returns: A python data structure, described with detail in
                  :meth:`load_bulk`
        """
    raise NotImplementedError
