code: def test_preprocessing_normalisation(self):
      classifier = ClassifierInstance()
  
      x = np.random.rand(2, 3)
      x_new, _ = classifier._apply_preprocessing(x=x, y=None, fit=False)
      x_new_expected = np.asarray(
          [
              [0.19151945, 0.62210877, 0.43772774],
              [0.78535858, 0.77997581, 0.27259261],
          ]
      )
      np.testing.assert_array_almost_equal(x_new, x_new_expected)
  
imports: from __future__ import absolute_import, division, print_function, unicode_literals
  import logging
  import unittest
  import numpy
  from art.estimators.classification.classifier import ClassGradientsMixin, ClassifierMixin
  from art.estimators.estimator import BaseEstimator, LossGradientsMixin, NeuralNetworkMixin
  from tests.utils import TestBase, master_seed
label_desc: Use image node_id 3 for calling the TestClassifier obj's underlying member method code with example usage: obj.test_preprocessing_normalisation() without return types