code: def dfs(self):
      yield self
      for child in self.children:
          yield from child.dfs()
  
imports: from abc import ABC, abstractmethod
  from collections import deque
  from typing import Any, List
  from evadb.plan_nodes.types import PlanOprType
label_desc: Use image node_id 14 for calling the AbstractPlan obj's underlying member method code with example usage: obj.dfs() without return types