code: def get_children_count(self) -> int:
      return len(self._children)
  
imports: from abc import ABC, abstractmethod
  from collections import deque
  from copy import deepcopy
  from enum import IntEnum, auto, unique
  from typing import Any
label_desc: Use image node_id 6 for calling the AbstractExpression obj's underlying member method code with example usage: obj.get_children_count() and returns: len