code: def test_call(self):
      def my_function(x):
          return x
  
      graph, _, _ = dot.to_graph(jax.jit(my_function))(jnp.ones([]))
      self.assertEmpty(graph.nodes)
      self.assertEmpty(graph.edges)
      (jit,) = graph.subgraphs
      self.assertIn(jit.title, ("pjit (my_function)",))
  
imports: from absl.testing import absltest
  from absl.testing import parameterized
  from haiku._src import dot
  from haiku._src import module
  from haiku._src import test_utils
  import jax
  import jax.numpy
label_desc: Use image node_id 4 for calling the DotTest obj's underlying member method code with example usage: obj.test_call() and returns: x