code: def build_model():
      import tensorflow as tf
  
      model = tf.keras.Sequential(
          [
              tf.keras.layers.InputLayer(input_shape=()),
              tf.keras.layers.Flatten(),
              tf.keras.layers.Dense(1),
          ]
      )
  
      return model
  
file_path: ray/python/ray/train/tests/test_tensorflow_trainer.py
imports: import os
  import tempfile
  import pytest
  import ray
  from ray import train
  from ray.data.preprocessors import Concatenator
  from ray.train import ScalingConfig
  from ray.train.constants import TRAIN_DATASET_KEY
  from ray.train.examples.tf.tensorflow_regression_example import train_func
  from ray.train.tensorflow import TensorflowCheckpoint, TensorflowTrainer
label_desc: Use image node_id 2 for calling a global function with example usage: build_model() and returns: model