code: def trainer(self):
      # Create a default BaseNNTrainer for testing.
      return BaseNNTrainer(None, 5)
  
imports: import pytest
  import torch
  import torch.nn
  from torch.utils.data import DataLoader, TensorDataset
  from kale.embed.image_cnn import SimpleCNNBuilder
  from kale.pipeline.base_nn_trainer import BaseNNTrainer, CNNTransformerTrainer, MultimodalNNTrainer
  from kale.predict.class_domain_nets import ClassNet
label_desc: Use image node_id 1 for calling the TestBaseTrainer obj's underlying member method code with example usage: obj.trainer() and returns: BaseNNTrainer