code: def serving_model_dir(
      output_uri: str, is_old_artifact: bool = False
  ) -> str:
      """Returns directory for exported model for serving purpose."""
      if is_old_artifact:
          return os.path.join(output_uri, _OLD_SERVING_MODEL_DIR)
      return os.path.join(output_uri, path_constants.SERVING_MODEL_DIR)
  
file_path: tfx/tfx/utils/path_utils.py
imports: import os
  import absl
  from tfx.dsl.io import fileio
  from tfx.types import artifact
  from tfx.types import artifact_utils
  from tfx.types import standard_artifacts
  from tfx.utils import io_utils
  from tfx.utils import path_constants
label_desc: Use image node_id 4 for calling a global function with example usage: serving_model_dir(output_uri, is_old_artifact) and returns: os, os