code: def pack_optimizer_state(marked_pytree):
      """Converts a marked pytree to an OptimizerState.
  
      The inverse of unpack_optimizer_state. Converts a marked pytree with the
      leaves of the outer pytree represented as JoinPoints back into an
      OptimizerState. This function is intended to be useful when deserializing
      optimizer states.
  
      Args:
        marked_pytree: A pytree containing JoinPoint leaves that hold more pytrees.
      Returns:
        An equivalent OptimizerState to the input argument.
      """
      sentinels, tree_def = tree_flatten(marked_pytree)
      assert all(isinstance(s, JoinPoint) for s in sentinels)
      subtrees = [s.subtree for s in sentinels]
      states_flat, subtree_defs = unzip2(map(tree_flatten, subtrees))
      return OptimizerState(states_flat, tree_def, subtree_defs)
  
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 20 for calling a global function with example usage: pack_optimizer_state(marked_pytree) and returns: OptimizerState