code: def test_convert_to_unicode(self):
      def dataset1():
          yield (
              b"Audentes fortuna iuvat.",
              b"Fortune favors the bold.",
          )
  
      def dataset2():
          yield (b"\x81aabb", b"Value")
  
      convert_function1 = tf_inputs.ConvertToUnicode(keys=[0])
      convert_output1 = next(convert_function1(dataset1()))
      self.assertEqual(convert_output1[0], "Audentes fortuna iuvat.")
      self.assertEqual(convert_output1[1], b"Fortune favors the bold.")
      self.assertIsInstance(convert_output1[0], str)
      self.assertIsInstance(convert_output1[1], bytes)
  
      # Contains an invalid bytes array from the point of view of UTF-8.
      try:
          convert_function2 = tf_inputs.ConvertToUnicode(keys=[0])
          convert_output2 = next(convert_function2(dataset2()))
      except UnicodeDecodeError:
          self.fail("ConvertToUnicode threw UnicodeDecodeError.")
      self.assertEqual(convert_output2[0], "aabb")
      self.assertIsInstance(convert_output2[0], str)
  
imports: import collections
  import os
  from unittest import mock
  import gin
  import numpy
  from t5.data import assert_dataset
  from t5.data import preprocessors
  import tensorflow
  import tensorflow_datasets
  from trax.data import inputs
  from trax.data import tf_inputs
label_desc: Use image node_id 6 for calling the TFInputsTest obj's underlying member method code with example usage: obj.test_convert_to_unicode() without return types