"class method."
            )
            if "llm_chain" not in values and values["llm"] is not None:
                database = values["database"]
                prompt = values.get("prompt") or SQL_PROMPTS.get(
                    database.dialect, PROMPT
                )
                values["llm_chain"] = LLMChain(llm=values["llm"], prompt=prompt)
        return values
    @property
    def input_keys(self) -> List[str]:
        """Return the singular input key.
        :meta private:
        """
        return [self.input_key]
    @property
    def output_keys(self) -> List[str]:
        """Return the singular output key.
        :meta private:
        """
        if not self.return_intermediate_steps:
            return [self.output_key]
        else:
            return [self.output_key, INTERMEDIATE_STEPS_KEY]
    def _call(
        self,
        inputs: Dict[str, Any],
        run_manager: Optional[CallbackManagerForChainRun] = None,
    ) -> Dict[str, Any]:
        _run_manager = run_manager or CallbackManagerForChainRun.get_noop_manager()
        input_text = f"{inputs[self.input_key]}\nSQLQuery:"
        _run_manager.on_text(input_text, verbose=self.verbose)
        # If not present, then defaults to None which is all tables.
        table_names_to_use = inputs.get("table_names_to_use")
        table_info = self.database.get_table_info(table_names=table_names_to_use)
        llm_inputs = {
            "input": input_text,
            "top_k": str(self.top_k),
            "dialect": self.database.dialect,
            "table_info": table_info,