code: def create_train_step() -> tf.Variable:
      return tf.Variable(
          0,
          trainable=False,
          dtype=tf.int64,
          aggregation=tf.VariableAggregation.ONLY_FIRST_REPLICA,
          shape=(),
      )
  
file_path: agents/tf_agents/train/utils/train_utils.py
imports: import os
  import time
  from typing import Callable, Text, Tuple
  from absl import logging
  import tensorflow.compat.v2
  from tf_agents.agents import tf_agent
  from tf_agents.policies import py_tf_eager_policy
  from tf_agents.typing import types
  from tf_agents.utils import lazy_loader
label_desc: Use image node_id 1 for calling a global function with example usage: create_train_step() and returns: tf