code: def _process_node(self, entity: EntityType):
      if entity.key in self._processed_chunks:
          if entity not in self._chunk_to_fetch:
              # gen fetch
              fetch_chunk = build_fetch(entity).data
              self._chunk_to_fetch[entity] = fetch_chunk
          return self._chunk_to_fetch[entity]
      return entity
  
imports: import dataclasses
  import functools
  from typing import Callable, Dict, Generator, Iterable, List, Optional, Set, Type, Union
  from ....core import FUSE_CHUNK_TYPE, CHUNK_TYPE, TILEABLE_TYPE
  from ....typing import EntityType, TileableType, ChunkType
  from ....utils import copy_tileables, build_fetch
  from ...entity.tileables import handler
  from ...mode import enter_mode
  from ..entity import TileableGraph, ChunkGraph
  from .base import AbstractGraphBuilder
label_desc: Use image node_id 2 for calling the ChunkGraphBuilder obj's underlying member method code with example usage: obj._process_node(entity) and returns: entity, self