def METHOD_NAME(self):
    assert list(
        traverse_post_order(
            start_node='b1',
            get_children=(lambda node: self.parent_to_children_map[node]),
            filter_func=(lambda node: (node != 'd3')))
    ) == ['e1', 'd1', 'f1', 'e2', 'd2', 'c1', 'c2', 'b1']