code: def test_errors(self):
      for x, y in [
          (1, [2, 3, 4]),  # x has no __len__
          ([1, 2], [3, 4, 5]),  # x and y are different lengths
      ]:
          with self.assertRaises(ValueError):
              NumpyDataGenerator(np.array(x), np.array(y))
  
imports: from __future__ import absolute_import, division, print_function, unicode_literals
  import logging
  import unittest
  import tensorflow
  import numpy
  from keras.preprocessing.image import ImageDataGenerator
  from art.data_generators import KerasDataGenerator, PyTorchDataGenerator, MXDataGenerator, TensorFlowDataGenerator
  from art.data_generators import TensorFlowV2DataGenerator, NumpyDataGenerator
  from tests.utils import master_seed
label_desc: Use image node_id 3 for calling the TestNumpyDataGenerator obj's underlying member method code with example usage: obj.test_errors() without return types