langchain/tools/powerbi/tool.py/QueryPowerBITool/validate_llm_chain_input_variables
class QueryPowerBITool:    def validate_llm_chain_input_variables(  # pylint: disable=E0213
        cls, llm_chain: LLMChain
    ) -> LLMChain:
        """Make sure the LLM chain has the correct input variables."""
        if llm_chain.prompt.input_variables != [
            "tool_input",
            "tables",
            "schemas",
            "examples",
        ]:
            raise ValueError(
                "LLM chain for QueryPowerBITool must have input variables ['tool_input', 'tables', 'schemas', 'examples'], found %s",  # noqa: C0301 E501 # pylint: disable=C0301
                llm_chain.prompt.input_variables,
            )
        return llm_chain