class_docstr: An online Q-lambda agent.
class_docstr_tok: ["An","online","Q-lambda","agent","."]
code: def learner_step(self, params, data, learner_state, unused_key):
      dloss_dtheta = jax.grad(self._loss)(params, *data)
      updates, learner_state = self._optimizer.update(
          dloss_dtheta, learner_state
      )
      params = optax.apply_updates(params, updates)
      return params, learner_state
  
imports: import collections
  from absl import app
  from absl import flags
  from bsuite.environments import catch
  import dm_env
  import haiku
  from haiku import nets
  import jax
  import jax.numpy
  import numpy
  import optax
  import rlax
  from rlax.examples import experiment
label_desc: Use image node_id 6 for calling the OnlineQLambda obj's underlying member method code with example usage: obj.learner_step(params, data, learner_state, unused_key) and returns: params,  learner_state