langchain/llms/predictionguard.py/PredictionGuard/validate_environment
class PredictionGuard:    def validate_environment(cls, values: Dict) -> Dict:
        """Validate that the access token and python package exists in environment."""
        token = get_from_dict_or_env(values, "token", "PREDICTIONGUARD_TOKEN")
        try:
            import predictionguard as pg

            values["client"] = pg.Client(token=token)
        except ImportError:
            raise ImportError(
                "Could not import predictionguard python package. "
                "Please install it with `pip install predictionguard`."
            )
        return values