def METHOD_NAME(file_importer: TrainingDataImporter) -> None:
    """Verifies that config contains a unique value for assistant identifier."""
    config_data = file_importer.get_config()
    assistant_id = config_data.get(ASSISTANT_ID_KEY)
    if assistant_id is None or assistant_id == ASSISTANT_ID_DEFAULT_VALUE:
        rasa.shared.utils.cli.print_error_and_exit(
            f"The '{ASSISTANT_ID_KEY}' key in the config file is either missing or "
            f"is set to the default value. Please replace the placeholder default "
            f"value and re-train the model."
        )
    return None