code: def main(_):
      hparams = trainer_lib.create_hparams(
          FLAGS.hparams_set, FLAGS.hparams
      )
  
      tf.logging.info("Starting model free training.")
      train(hparams, FLAGS.output_dir, FLAGS.env_problem_name)
      tf.logging.info("Ended model free training.")
  
file_path: tensor2tensor/tensor2tensor/rl/trainer_model_free.py
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import os
  import pprint
  from tensor2tensor.models.research import rl
  from tensor2tensor.rl import rl_utils
  from tensor2tensor.utils import flags
  from tensor2tensor.utils import misc_utils
  from tensor2tensor.utils import registry
  from tensor2tensor.utils import trainer_lib
  import tensorflow.compat.v1
label_desc: Use image node_id 3 for calling a global function with example usage: main(_) without return types