code: def save(saver, session, ckpt_dir, ckpt_name="best"):
      """Save model checkpoint."""
      if not os.path.exists(ckpt_dir):
          os.makedirs(ckpt_dir)
          logging.info("make dir: {}".format(ckpt_dir))
      ckpt_path = os.path.join(ckpt_dir, ckpt_name)
      logging.info("[*] saving checkpoints to {}...".format(ckpt_path))
      saver.save(session, ckpt_path)
  
file_path: delta/delta/utils/model.py
imports: import os
  import numpy
  import hurry.filesize
  from absl import logging
  import delta.compat
  from tensorflow.python.framework import graph_util
label_desc: Use image node_id 3 for calling a global function with example usage: save(saver, session, ckpt_dir, ckpt_name) without return types