code: def _get_callback(model_dir):
      """Create callbacks for Keras model training."""
      check_point = tf.keras.callbacks.ModelCheckpoint(
          save_best_only=True,
          filepath=os.path.join(model_dir, "model.ckpt-{epoch:04d}"),
          verbose=1,
      )
      tensorboard = tf.keras.callbacks.TensorBoard(
          log_dir=model_dir, update_freq=100
      )
      return [check_point, tensorboard]
  
file_path: model-optimization/tensorflow_model_optimization/python/examples/cluster_preserve_qat/keras/mnist_cnn.py
imports: from __future__ import print_function
  import os
  from absl import app
  import numpy
  import tensorflow
  from tensorflow_model_optimization.python.core.clustering.keras import cluster
  from tensorflow_model_optimization.python.core.clustering.keras import cluster_config
  from tensorflow_model_optimization.python.core.quantization.keras import quantize
  from tensorflow_model_optimization.python.core.quantization.keras.collab_opts.cluster_preserve import default_8bit_cluster_preserve_quantize_scheme
  from tensorflow_model_optimization.python.core.quantization.keras.collab_opts.cluster_preserve.cluster_utils import strip_clustering_cqat
label_desc: Use image node_id 2 for calling a global function with example usage: _get_callback(model_dir) and returns: list