code: def _resolve_and_ensure_boolean(
      resolve_fn: Callable[
          [placeholder_pb2.PlaceholderExpression], Any
      ],
      expression: placeholder_pb2.PlaceholderExpression,
      error_message: str,
  ) -> bool:
      # TODO(b/173529355): Block invalid placeholders during compilation time
      """Ensures that expression resolves to boolean.
  
      NOTE: This is currently used to ensure that the inputs to logical operators
      are boolean. Since the DSL for creating Predicate expressions do not currently
      perform implicit boolean conversions, the evaluator should not support it
      either. If we support implicit boolean conversions in the DSL in the
      future, this check can be removed.
  
      Args:
        resolve_fn: The function for resolving placeholder expressions.
        expression: The placeholder expression to resolve.
        error_message: The error message to display if the expression does not
          resolve to a boolean type.
  
      Returns:
        The resolved boolean value.
  
      Raises:
        ValueError if expression does not resolve to boolean type.
      """
      value = resolve_fn(expression)
      if isinstance(value, bool):
          return value
      raise ValueError(
          f"{error_message}\n"
          f"expression: {expression}\n"
          f"resolved value type: {type(value)}\n"
          f"resolved value: {value}"
      )
  
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 2 for calling a global function with example usage: _resolve_and_ensure_boolean(resolve_fn, expression, error_message) and returns: value