code: def _veryify_root_dir(
      self, output_uri: str, unused_artifact_uri: str
  ):
      self.assertTrue(fileio.exists(output_uri))
  
imports: import os
  from absl import logging
  import tensorflow
  from tfx.dsl.compiler import compiler
  from tfx.dsl.io import fileio
  from tfx.examples.imdb import imdb_pipeline_native_keras
  from tfx.experimental.pipeline_testing import executor_verifier_utils
  from tfx.experimental.pipeline_testing import pipeline_mock
  from tfx.experimental.pipeline_testing import pipeline_recorder_utils
  from tfx.orchestration import metadata
  from tfx.orchestration.beam.beam_dag_runner import BeamDagRunner
  from ml_metadata.proto import metadata_store_pb2
label_desc: Use image node_id 3 for calling the ImdbStubPipelineRegressionEndToEndTest obj's underlying member method code with example usage: obj._veryify_root_dir(output_uri, unused_artifact_uri) without return types