code: def unpack_optimizer_state(opt_state):
      """Converts an OptimizerState to a marked pytree.
  
      Converts an OptimizerState to a marked pytree with the leaves of the outer
      pytree represented as JoinPoints to avoid losing information. This function is
      intended to be useful when serializing optimizer states.
  
      Args:
        opt_state: An OptimizerState
      Returns:
        A pytree with JoinPoint leaves that contain a second level of pytrees.
      """
      states_flat, tree_def, subtree_defs = opt_state
      subtrees = map(tree_unflatten, subtree_defs, states_flat)
      sentinels = [JoinPoint(subtree) for subtree in subtrees]
      return tree_util.tree_unflatten(tree_def, sentinels)
  
imports: from __future__ import annotations
  from typing import Any, Callable, NamedTuple
  from collections import namedtuple
  import functools
  from functools import partial
  import jax.numpy
  from jax._src.util import safe_zip, safe_map, unzip2
  from jax import tree_util
  from jax.tree_util import tree_map, tree_flatten, tree_unflatten, register_pytree_node
label_desc: Use image node_id 19 for calling a global function with example usage: unpack_optimizer_state(opt_state) and returns: tree_util