code: def build_graph_from_json(ir_model_json):
      """build model from json representation"""
      graph = json_to_graph(ir_model_json)
      logging.debug(graph.operation_history)
      model = graph.produce_keras_model()
      return model
  
file_path: nni/examples/trials/network_morphism/FashionMNIST/FashionMNIST_keras.py
imports: import argparse
  import logging
  import os
  import tensorflow
  import keras
  from keras.callbacks import EarlyStopping, TensorBoard
  from keras.datasets import fashion_mnist
  from keras.optimizers import SGD, Adadelta, Adagrad, Adam, Adamax, RMSprop
  from keras.utils import multi_gpu_model, to_categorical
  import keras.backend.tensorflow_backend
  import nni
  from nni.networkmorphism_tuner.graph import json_to_graph
label_desc: Use image node_id 2 for calling a global function with example usage: build_graph_from_json(ir_model_json) and returns: model