langchain/utilities/metaphor_search.py/MetaphorSearchAPIWrapper/validate_environment
class MetaphorSearchAPIWrapper:    def validate_environment(cls, values: Dict) -> Dict:
        """Validate that api key and endpoint exists in environment."""
        metaphor_api_key = get_from_dict_or_env(
            values, "metaphor_api_key", "METAPHOR_API_KEY"
        )
        values["metaphor_api_key"] = metaphor_api_key

        return values