code: def test_pass_empty_classes_raises(
      self, net_cls, module_cls, data, classes
  ):
      net = (
          net_cls(module_cls, max_epochs=0, classes=classes)
          .fit(*data)
          .fit(*data)
      )
      with pytest.raises(AttributeError) as exc:
          net.classes_  # pylint: disable=pointless-statement
  
      msg = exc.value.args[0]
      expected = "NeuralNetClassifier has no attribute 'classes_'"
      assert msg == expected
  
imports: from unittest.mock import Mock
  import numpy
  import pytest
  import torch
  from scipy.special import expit
  from sklearn.base import clone
  from torch import nn
  from skorch.tests.conftest import INFERENCE_METHODS
label_desc: Use image node_id 20 for calling the TestNeuralNet obj's underlying member method code with example usage: obj.test_pass_empty_classes_raises(net_cls, module_cls, data, classes) without return types