code: def on_train_begin(self, logs=None):
      self.img_secs = []
  
file_path: horovod/examples/tensorflow2/tensorflow2_keras_synthetic_benchmark.py
imports: import argparse
  import os
  import numpy
  from timeit import default_timer
  import tensorflow
  import horovod.tensorflow.keras
  from tensorflow.keras import applications
label_desc: Use image node_id 1 for calling the TimingCallback obj's underlying member method code with example usage: obj.on_train_begin(logs) without return types