code: def test_simple_expression(self):
      def add(x, y):
          return jnp.sign(x) + jnp.cos(y)
  
      a = jnp.zeros((12, 7))
      mod = jaxpr_info.make_model_info(add)(a, a)
      self.assertContentsEqual(
          jaxpr_info.format_module(mod),
          """
  add
    sign
      sign in f32[12,7], out f32[12,7]
    cos in f32[12,7], out f32[12,7]
    add in f32[12,7], f32[12,7], out f32[12,7]
  """,
      )
  
imports: from typing import Optional
  from absl import logging
  from absl.testing import absltest
  from haiku._src import conv
  from haiku._src import jaxpr_info
  from haiku._src import module
  from haiku._src import transform
  import jax
  import jax.numpy
  import numpy
label_desc: Use image node_id 1 for calling the JaxprInfoTest obj's underlying member method code with example usage: obj.test_simple_expression() and returns: unknown