code: def test_initialize_class_weights_balanced(
      self, mock_current_device, mock_is_available
  ):
      mock_current_device.return_value = "0"
      mock_is_available.return_value = True
  
      clf = SimplePytorchClassifier(
          3, multi_label=True, class_weight="balanced"
      )
      train_set = random_text_classification_dataset(
          max_length=10, num_classes=3
      )
      class_weights = clf.initialize_class_weights(train_set)
  
      self.assertIsNotNone(class_weights)
  
imports: import pytest
  import unittest
  from unittest.mock import Mock, patch
  from small_text.integrations.pytorch.exceptions import PytorchNotFoundError
  from small_text.training.model_selection import ModelSelection, NoopModelSelection
  from tests.utils.datasets import random_text_classification_dataset
label_desc: Use image node_id 13 for calling the SimplePytorchClassifierTest obj's underlying member method code with example usage: obj.test_initialize_class_weights_balanced(mock_current_device, mock_is_available) without return types