code: def test_initialize_class_weights_binary_no_class_weights(self):
      sub_train = random_text_classification_dataset(10)
      classifier = PytorchClassifierImplementation(2)
      class_weights = classifier.initialize_class_weights(sub_train)
  
      self.assertIsNone(class_weights)
  
imports: import unittest
  import pytest
  import torch
  import numpy
  from small_text.integrations.pytorch.exceptions import PytorchNotFoundError
label_desc: Use image node_id 4 for calling the PytorchClassifierTest obj's underlying member method code with example usage: obj.test_initialize_class_weights_binary_no_class_weights() without return types