code: def test_train(self):
      def nullifier(*args):
          pass
  
      mockd_trainer = copy(self.trainer)
      mockd_trainer.logger = Mock(side_effect=nullifier)
      mockd_trainer.valid_dh.get_validation_set = Mock(
          return_value={"lr": [], "hr": []}
      )
      mockd_trainer.train_dh.get_batch = Mock(
          return_value={"lr": [], "hr": []}
      )
      mockd_trainer.feature_extractor.model.predict = Mock(
          return_value=[]
      )
      mockd_trainer.generator.model.predict = Mock(return_value=[])
      mockd_trainer.discriminator.model.train_on_batch = Mock(
          return_value=[]
      )
      mockd_trainer.model.train_on_batch = Mock(return_value=[])
      mockd_trainer.model.evaluate = Mock(return_value=[])
      mockd_trainer.tensorboard = Mock(side_effect=nullifier)
      mockd_trainer.helper.on_epoch_end = Mock(return_value=True)
  
      logging.disable(logging.CRITICAL)
      mockd_trainer.train(
          epochs=1,
          steps_per_epoch=1,
          batch_size=1,
          monitored_metrics={},
      )
  
imports: import logging
  import os
  import shutil
  import unittest
  from copy import copy
  from pathlib import Path
  import yaml
  import numpy
  from unittest.mock import patch, Mock
  from ISR.models.cut_vgg19 import Cut_VGG19
  from ISR.models.discriminator import Discriminator
  from ISR.models.rrdn import RRDN
  from ISR.train.trainer import Trainer
label_desc: Use image node_id 12 for calling the TrainerClassTest obj's underlying member method code with example usage: obj.test_train() without return types