code: def test_discrete_actions(self, loss_name):
      with chex.fake_pmap_and_jit():
          num_sgd_steps_per_step = 1
          num_steps = 5
  
          # Create a fake environment to test with.
          environment = fakes.DiscreteEnvironment(
              num_actions=10,
              num_observations=100,
              obs_shape=(10,),
              obs_dtype=np.float32,
          )
  
          spec = specs.make_environment_spec(environment)
          dataset_demonstration = fakes.transition_dataset(environment)
          dataset_demonstration = dataset_demonstration.map(
              lambda sample: types.Transition(*sample.data)
          )
          dataset_demonstration = dataset_demonstration.batch(
              8
          ).as_numpy_iterator()
  
          # Construct the agent.
          networks = make_networks(spec, discrete_actions=True)
  
          if loss_name == "logp":
              loss_fn = bc.logp()
  
          elif loss_name == "rcal":
              base_loss_fn = bc.logp()
              loss_fn = bc.rcal(base_loss_fn, discount=0.99, alpha=0.1)
  
          else:
              raise ValueError
  
          learner = bc.BCLearner(
              networks=networks,
              random_key=jax.random.PRNGKey(0),
              loss_fn=loss_fn,
              optimizer=optax.adam(0.01),
              prefetching_iterator=utils.sharded_prefetch(
                  dataset_demonstration
              ),
              num_sgd_steps_per_step=num_sgd_steps_per_step,
          )
  
          # Train the agent
          for _ in range(num_steps):
              learner.step()
  
imports: from acme import specs
  from acme import types
  from acme.agents.jax import bc
  from acme.jax import networks
  from acme.jax import types
  from acme.jax import utils
  from acme.testing import fakes
  import chex
  import haiku
  import jax
  import jax.numpy
  from jax.scipy import special
  import numpy
  import optax
  import rlax
  from absl.testing import absltest
  from absl.testing import parameterized
label_desc: Use image node_id 2 for calling the BCTest obj's underlying member method code with example usage: obj.test_discrete_actions(loss_name) without return types