code: def test_from_json_content_backward_compatibility():
      legacy_json = {
          "type": "tensorflow_datasets.core.features.features_dict.FeaturesDict",
          "content": {
              "input": {
                  "type": "tensorflow_datasets.core.features.image_feature.Image",
                  "content": {
                      "shape": [28, 28, 3],
                      "dtype": "uint8",
                      "encoding_format": "png",
                  },
              },
              "target": {
                  "type": "tensorflow_datasets.core.features.class_label_feature.ClassLabel",
                  "content": {"num_classes": 10},
              },
          },
      }
      parsed_features_dict = features_lib.FeatureConnector.from_json(
          legacy_json
      )
      assert parsed_features_dict.keys() == set(["input", "target"])
  
imports: import pathlib
  import sys
  import textwrap
  from unittest import mock
  from absl import logging
  from absl.testing import parameterized
  import numpy
  import tensorflow
  from tensorflow_datasets import testing
  from tensorflow_datasets.core import features
label_desc: Use image node_id 3 for calling a global function with example usage: test_from_json_content_backward_compatibility() without return types