code: def _referenced_artifact_id(self):
      return None
  
imports: import os
  import platform
  import pytest
  import wandb
  from wandb.sdk.artifacts.artifact import Artifact
  from wandb.sdk.artifacts.artifact_manifest_entry import ArtifactManifestEntry
  from wandb.sdk.data_types import saved_model
  from wandb.sdk.lib.filesystem import copy_or_overwrite_changed
  from .None import saved_model_constructors
label_desc: Use image node_id 2 for calling the ArtifactManifestEntryPatch obj's underlying member method code with example usage: obj._referenced_artifact_id() and returns: None