code: def current_grid_env() -> tuple[GridEnv, ...] | None:
      if not _grid_env_stack:
          return None
      return _grid_env_stack[-1]
  
imports: from __future__ import annotations
  from collections.abc import Sequence
  import contextlib
  import dataclasses
  import functools
  from typing import Any, Callable
  from collections.abc import Iterator
  from jax._src import api_util
  from jax._src import core
  from jax._src import linear_util
  from jax._src import state
  from jax._src import tree_util
  from jax._src import util
  from jax._src.interpreters import partial_eval
  from jax._src.state import discharge
  import jax.numpy
label_desc: Use image node_id 2 for calling a global function with example usage: current_grid_env() and returns: _grid_env_stack, None