code: def testAutoregisterTrainable(self):
      class B(Trainable):
          def step(self):
              return {"timesteps_this_iter": 1, "done": True}
  
      register_trainable("f1", train_fn)
      trials = run_experiments(
          {
              "foo": {
                  "run": train_fn,
              },
              "bar": {"run": B},
          }
      )
      for trial in trials:
          self.assertEqual(trial.status, Trial.TERMINATED)
  
imports: import os
  import unittest
  import ray
  import ray.train
  from ray.train import CheckpointConfig
  from ray.rllib import _register_all
  from ray.tune.result import TIMESTEPS_TOTAL
  from ray.tune import Trainable, TuneError
  from ray.tune import register_trainable, run_experiments
  from ray.tune.logger import LegacyLoggerCallback, Logger
  from ray.tune.experiment import Experiment
  from ray.tune.experiment.trial import Trial, ExportFormat
label_desc: Use image node_id 6 for calling the RunExperimentTest obj's underlying member method code with example usage: obj.testAutoregisterTrainable() and returns: dict