langchain/utilities/twilio.py/TwilioAPIWrapper/validate_environment
class TwilioAPIWrapper:    def validate_environment(cls, values: Dict) -> Dict:
        """Validate that api key and python package exists in environment."""
        try:
            from twilio.rest import Client
        except ImportError:
            raise ImportError(
                "Could not import twilio python package. "
                "Please install it with `pip install twilio`."
            )
        account_sid = get_from_dict_or_env(values, "account_sid", "TWILIO_ACCOUNT_SID")
        auth_token = get_from_dict_or_env(values, "auth_token", "TWILIO_AUTH_TOKEN")
        values["from_number"] = get_from_dict_or_env(
            values, "from_number", "TWILIO_FROM_NUMBER"
        )
        values["client"] = Client(account_sid, auth_token)
        return values