code: def tree_flatten(self):
      flat_idx, idx_tree = tree_util.tree_flatten(self.indices)
      return flat_idx, (idx_tree, self.shape, self.int_indexer_shape)
  
imports: from __future__ import annotations
  import dataclasses
  from typing import Any, Union
  from jax._src import core
  from jax._src import tree_util
  from jax._src.typing import Array
  from jax._src.util import merge_lists
  from jax._src.util import partition_list
  import numpy
label_desc: Use image node_id 2 for calling the NDIndexer obj's underlying member method code with example usage: obj.tree_flatten() and returns: flat_idx,  idx_tree,  self,  self