code: def __init__(self, *args):
      super(LRChecker, self).__init__(*args)
  
      self.warmup_lr = [0.16, 0.22, 0.28, 0.34, 0.4]
  
imports: import os
  from unittest import TestCase
  import numpy
  import pytest
  import tensorflow
  from bigdl.orca.learn.tf2 import Estimator
  from bigdl.orca.ray import OrcaRayContext
  from bigdl.orca import OrcaContext
label_desc: Use image node_id 1 to create a new LRChecker object from inherited base classes: tf.keras.callbacks with example: obj = LRChecker()