docs: def MigrateArtifacts():
    """Migrates Artifacts from AFF4 to REL_DB."""
  
    # First, delete all existing artifacts in REL_DB.
    artifacts = data_store.REL_DB.ReadAllArtifacts()
    if artifacts:
      logging.info("Deleting %d artifacts from REL_DB.", len(artifacts))
      for artifact in data_store.REL_DB.ReadAllArtifacts():
        data_store.REL_DB.DeleteArtifact(Text(artifact.name))
    else:
      logging.info("No artifacts found in REL_DB.")
  
    artifacts = artifact_registry.REGISTRY.GetArtifacts(
        reload_datastore_artifacts=True)
  
    logging.info("Found %d artifacts in AFF4.", len(artifacts))
  
    # Only migrate user-created artifacts.
    artifacts = list(filter(_IsCustom, artifacts))
  
    logging.info("Migrating %d user-created artifacts.", len(artifacts))
  
    for artifact in artifacts:
      _MigrateArtifact(artifact)