code: def test_state(self):
      def f():
          def init():
              s = base.get_state("s", [], init=jnp.zeros)
              base.set_state("s", s + 1)
  
          def apply():
              s = base.get_state("s")
              base.set_state("s", s + 1)
  
          return init, apply
  
      f = multi_transform.multi_transform_with_state(f)
      _, state_in = f.init(None)
      self.assertEqual(state_in, {"~": {"s": 0}})
      _, state_out = f.apply({}, state_in, None)
      self.assertEqual(state_out, {"~": {"s": 1}})
  
imports: import inspect
  from typing import Optional, Union
  from absl.testing import absltest
  from absl.testing import parameterized
  from haiku._src import base
  from haiku._src import multi_transform
  from haiku._src import transform
  from haiku._src import typing
  import jax
  import jax.numpy
  import numpy
label_desc: Use image node_id 4 for calling the MultiTransformTest obj's underlying member method code with example usage: obj.test_state() and returns: init,  apply