code: def test_layer_stack_no_state_error(self):
      def outer_fn_layer_stack(x):
          stack = layer_stack.layer_stack(1)(
              lambda x: base.set_state("hi", x)
          )
          return stack(x)
  
      layer_stack_fn = transform.transform_with_state(
          outer_fn_layer_stack
      )
  
      x = jnp.ones((1,))
  
      with self.assertRaisesRegex(
          layer_stack.LayerStackStateError, "LayerStack.*state"
      ):
          layer_stack_fn.init(None, x)
  
imports: import functools
  import re
  from typing import Optional
  from absl.testing import absltest
  from absl.testing import parameterized
  from haiku._src import base
  from haiku._src import basic
  from haiku._src import config
  from haiku._src import initializers
  from haiku._src import layer_stack
  from haiku._src import module
  from haiku._src import multi_transform
  from haiku._src import transform
  from haiku._src import utils
  import jax
  import jax.numpy
  import numpy
  from scipy import stats
label_desc: Use image node_id 6 for calling the LayerStackTest obj's underlying member method code with example usage: obj.test_layer_stack_no_state_error() and returns: stack