code: def add_child_node(self, child_node):
      self._node_children.append(child_node)
  
imports: import re
  import difflib
  from collections import namedtuple
  import logging
  from parso.utils import split_lines
  from parso.python.parser import Parser
  from parso.python.tree import EndMarker
  from parso.python.tokenize import PythonToken, BOM_UTF8_STRING
  from parso.python.token import PythonTokenTypes
label_desc: Use image node_id 3 for calling the _NodesTreeNode obj's underlying member method code with example usage: obj.add_child_node(child_node) without return types