code: def save(self, checkpoint_file, config_path=None):
      state_dict = self.state_dict()
      with open(checkpoint_file, "wb") as f:
          pickle.dump(state_dict, f)
  
imports: import pickle
  import numpy
  import time
  from tensorflow.keras.models import Model
  from tensorflow.keras.layers import *
  from tensorflow.keras.initializers import TruncatedNormal, Constant
  import tensorflow.keras.backend
  import tensorflow
  from bigdl.orca.automl.metrics import Evaluator
  from bigdl.orca.automl.model.abstract import BaseModel
label_desc: Use image node_id 15 for calling the MTNetKeras obj's underlying member method code with example usage: obj.save(checkpoint_file, config_path) without return types