text: import tensorflow as tf
  
  
  class LogHistory(tf.keras.callbacks.Callback):
      def on_train_begin(self, logs={}):
          self.batches = []
          self.epochs = []
  
      def _store_logs(self, storage, batch_or_epoch, logs={}):
          if [key for key in logs if "changed_quantization_ration" in key]:
              storage.append(batch_or_epoch)
  
      def on_batch_end(self, batch, logs={}):
          self._store_logs(self.batches, batch, logs)
  
      def on_epoch_end(self, epoch, logs={}):
          self._store_logs(self.epochs, epoch, logs)
  
  
  class TestHyperparameterScheduler:
      pass
  