code: def train_fn(config):
      for i in range(100):
          ray.train.report(dict(timesteps_total=i))
  
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 1 for calling a global function with example usage: train_fn(config) without return types