class_docstr: Model card field base class.
  
  This is an abstract class. All the model card fields should inherit this class
  and override the _proto_type property to the corresponding proto type. This
  abstract class provides methods `from_proto`, `merge_from_proto` and
  `to_proto` to convert the class from and to proto. The child class does not
  need to override this unless it needs some special process.
docstr: Constructs an object of this class from a model card proto.
docstr_tok: ["Constructs","an","object","of","this","class","from","a","model","card","proto","."]
code: def from_proto(cls: Type[T], proto: message.Message) -> T:
      """Constructs an object of this class from a model card proto."""
      return cls()._from_proto(proto)
  
imports: import abc
  import dataclasses
  import json
  from textwrap import dedent
  from typing import Any, Dict, Type, TypeVar
  from warnings import warn
  from google.protobuf import descriptor, message
  from model_card_toolkit.utils import json_utils
label_desc: Use image node_id 7 for calling the BaseModelCardField obj's underlying member method code with example usage: obj.from_proto(cls, proto) and returns: cls