langchain/utilities/searx_search.py/SearxSearchWrapper/validate_params
class SearxSearchWrapper:    def validate_params(cls, values: Dict) -> Dict:
        """Validate that custom searx params are merged with default ones."""
        user_params = values["params"]
        default = _get_default_params()
        values["params"] = {**default, **user_params}

        engines = values.get("engines")
        if engines:
            values["params"]["engines"] = ",".join(engines)

        categories = values.get("categories")
        if categories:
            values["params"]["categories"] = ",".join(categories)

        searx_host = get_from_dict_or_env(values, "searx_host", "SEARX_HOST")
        if not searx_host.startswith("http"):
            print(
                f"Warning: missing the url scheme on host \
                ! assuming secure https://{searx_host} "
            )
            searx_host = "https://" + searx_host
        elif searx_host.startswith("http://"):
            values["unsecure"] = True
            cls.disable_ssl_warnings(True)
        values["searx_host"] = searx_host

        return values