code: def test_ignore_index_with_valid_index(self):
      accuracy = Accuracy(ignore_index=1)
      actual = accuracy(self.predictions, self.targets)
      self.assertEqual((), actual.shape)
      np.testing.assert_almost_equal(20.0, actual)
  
imports: from unittest import TestCase, skipIf
  import numpy
  import torch
  from poutyne import Accuracy, BinaryAccuracy, TopKAccuracy, acc, bin_acc, topk
label_desc: Use image node_id 6 for calling the IgnoreIndexAccuracyTest obj's underlying member method code with example usage: obj.test_ignore_index_with_valid_index() without return types