code: def fake_open(unused_path: str, unused_mode: str = "r") -> bool:
      """Mock behavior of fileio.open."""
      mock_open = mock.Mock()
      mock_open.contents = b""
      mock_open.read.side_effect = lambda: mock_open.contents
  
      def write_func(value):
          mock_open.contents = value
  
      mock_write = mock.Mock()
      mock_write.write.side_effect = write_func
      mock_open.__enter__ = mock_write
      mock_open.__exit__ = mock.Mock()
      return mock_open
  
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 3 for calling a global function with example usage: fake_open(unused_path, unused_mode) and returns: mock_open