code: def fake_isdir(path: str) -> bool:
      """Mock behavior of fileio.isdir."""
      return path in [_VALID_URI]
  
imports: import json
  from unittest import mock
  import tensorflow
  from tfx.dsl.io import fileio
  from tfx.types import standard_artifacts
  from tfx.types import system_artifacts
  from tfx.types import value_artifact
  from google.protobuf import json_format
  from ml_metadata.proto import metadata_store_pb2
label_desc: Use image node_id 2 for calling a global function with example usage: fake_isdir(path) and returns: unknown