code: def infer_last_epoch_num(data_dir):
      """Infer highest epoch number from file names in data_dir."""
      names = os.listdir(data_dir)
      epochs_str = [
          re.findall(pattern=r".*\.(-?\d+)$", string=name)
          for name in names
      ]
      epochs_str = sum(epochs_str, [])
      return max([int(epoch_str) for epoch_str in epochs_str])
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import copy
  import os
  import re
  import gym
  import numpy
  import six
  from tensor2tensor.models.research.rl import get_policy
  from tensor2tensor.models.research.rl import make_simulated_env_fn_from_hparams
  from tensor2tensor.rl import rl_utils
  from tensor2tensor.rl.envs.simulated_batch_gym_env import FlatBatchEnv
  from tensor2tensor.utils import hparam
  from tensor2tensor.utils import trainer_lib
  from tensor2tensor.utils.misc_utils import camelcase_to_snakecase
  import tensorflow.compat.v1
label_desc: Use image node_id 1 for calling a global function with example usage: infer_last_epoch_num(data_dir) and returns: max