code: def _checkpoint_path_or_none(checkpoint_filename):
      checkpoint = tfv1.train.get_checkpoint_state(
          FLAGS.load_checkpoint_dir, checkpoint_filename
      )
      if not checkpoint:
          return None
      return checkpoint.model_checkpoint_path
  
file_path: DeepSpeech/training/deepspeech_training/util/checkpoints.py
imports: import sys
  import tensorflow
  import tensorflow.compat.v1
  from .flags import FLAGS
  from .logging import log_info, log_error, log_warn
label_desc: Use image node_id 2 for calling a global function with example usage: _checkpoint_path_or_none(checkpoint_filename) and returns: checkpoint, None