class_docstr: `FeatureConnector` for integer class labels.
code: def from_json_content(
      cls, value: Union[Json, feature_pb2.ClassLabel]
  ) -> "ClassLabel":
      if isinstance(value, dict):
          return cls(**value)
      return cls(num_classes=value.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 12 for calling the ClassLabel obj's underlying member method code with example usage: obj.from_json_content(cls, value) and returns: cls, cls