code: def dfs_do_func_on_graph(node, func, *args, **kwargs):
      '''
      invoke func on each node of the dr graph
      '''
      for _node in node.tree_iterator():
          func(_node, *args, **kwargsf dfs_do_func_on_graph(node, func, *args, **kwargs):
      '''
      invoke func on each node of the dr graph
      '''
      for _node in node.tree_iterator():
          func(_node, *args, **kwargs)
docs: invoke func on each node of the dr graph