code: def test_that_discriminator_and_f_extr_are_not_trainable_in_combined_model(
      self,
  ):
      combined = self.trainer._combine_networks()
      self.assertTrue(
          combined.get_layer("discriminator").trainable == False
      )
      self.assertTrue(
          combined.get_layer("feature_extractor").trainable == False
      )
  
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 8 for calling the TrainerClassTest obj's underlying member method code with example usage: obj.test_that_discriminator_and_f_extr_are_not_trainable_in_combined_model() without return types