class_docstr: `FeatureConnector` for integer class labels.
code: def to_json_content(
      self,
  ) -> (
      feature_pb2.ClassLabel
  ):  # pytype: disable=signature-mismatch  # overriding-return-type-checks
      return feature_pb2.ClassLabel(num_classes=self.num_classes)
  
imports: from typing import Optional, Union
  from etils import epath
  import numpy
  from tensorflow_datasets.core.features import feature
  from tensorflow_datasets.core.features import tensor_feature
  from tensorflow_datasets.core.proto import feature_pb2
  from tensorflow_datasets.core.utils import type_utils
label_desc: Use image node_id 13 for calling the ClassLabel obj's underlying member method code with example usage: obj.to_json_content() and returns: feature_pb2