code: def test_custom_key(self, do_jit):
      if do_jit:
          self.skipTest(
              "init returns nothing, so compilation may DCE it"
          )
  
      count = 0
  
      def count_splits(_, num):
          nonlocal count
          count += 1
          num = tuple(num) if isinstance(num, Sequence) else (num,)
          return jnp.zeros((*num, 13), np.uint32)
  
      # TODO(frostig): remove after JAX 0.4.20, use
      # jex.random.define_prng_impl directly
      if hasattr(jex.random, "define_prng_impl"):
          def_prng_impl = jex.random.define_prng_impl
      else:
          def_prng_impl = jex.random.PRNGImpl
  
      differently_shaped_prng_impl = def_prng_impl(
          # Testing a different key shape to make sure it's accepted by Haiku
          key_shape=(13,),
          seed=lambda _: jnp.zeros((13,), np.uint32),
          split=count_splits,
          random_bits=lambda *_, data: jnp.zeros(data, np.uint32),
          fold_in=lambda key, _: key,
      )
  
      init, _ = transform.transform(base.next_rng_key)
      if do_jit:
          init = jax.jit(init)
      key = jax.random.key(42, impl=differently_shaped_prng_impl)
      init(key)
      self.assertEqual(count, 1)
  
imports: from collections.abc import Sequence
  import functools
  from absl.testing import absltest
  from absl.testing import parameterized
  from haiku._src import base
  from haiku._src import random
  from haiku._src import transform
  import jax
  import jax.extend
  import jax.numpy
  import numpy
label_desc: Use image node_id 2 for calling the CustomRNGTest obj's underlying member method code with example usage: obj.test_custom_key(do_jit) and returns: jnp