code: def _get_all_operators() -> Dict[str, Set[str]]:
      """Returns fields contained within operator_type messages, by field name."""
      return {
          op: set(f.name for f in desc.message_type.fields)
          for op, desc in placeholder_pb2.PlaceholderExpressionOperator.DESCRIPTOR.fields_by_name.items()
      }
  
imports: import base64
  import enum
  import functools
  import os
  import re
  from typing import Any, Callable, Dict, List, Set, Union, cast
  from absl import logging
  import attr
  from tfx.dsl.io import fileio
  from tfx.orchestration.portable import data_types
  from tfx.proto.orchestration import placeholder_pb2
  from tfx.types import artifact
  from tfx.types import artifact_utils
  from tfx.types import value_artifact
  from tfx.utils import json_utils
  from tfx.utils import proto_utils
  from google.protobuf import any_pb2
  from google.protobuf import descriptor
  from google.protobuf import json_format
  from google.protobuf import message
  from google.protobuf import text_format
label_desc: Use image node_id 5 for calling a global function with example usage: _get_all_operators() and returns: unknown