code: def test_tokenize_dict(self):
      def dataset():
          yield {"a": "Cat.", "b": "Dog."}
  
      tok_char1 = list(tf_inputs.tokenize(dataset(), vocab_type="char"))
      self.assertAllEqual(
          tok_char1[0]["a"], np.array([ord(c) for c in "Cat."])
      )
      self.assertAllEqual(
          tok_char1[0]["b"], np.array([ord(c) for c in "Dog."])
      )
  
      tok_char2 = list(
          tf_inputs.tokenize(dataset(), keys=["a"], vocab_type="char")
      )
      self.assertAllEqual(
          tok_char2[0]["a"], np.array([ord(c) for c in "Cat."])
      )
      self.assertEqual(tok_char2[0]["b"], "Dog.")
  
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 9 for calling the TFInputsTest obj's underlying member method code with example usage: obj.test_tokenize_dict() without return types