Method _invoke_before_exec_event

lib/sqlalchemy/engine/base.py:1576–1616

(
        self,
        elem: Any,
        distilled_params: _CoreMultiExecuteParams,
        execution_options: _ExecuteOptions,
    )

        return ret

    def _invoke_before_exec_event(
        self,
        elem: Any,
        distilled_params: _CoreMultiExecuteParams,
        execution_options: _ExecuteOptions,
    ) -> Tuple[
        Any,
        _CoreMultiExecuteParams,
        _CoreMultiExecuteParams,
        _CoreSingleExecuteParams,
    ]:
        event_multiparams: _CoreMultiExecuteParams
        event_params: _CoreSingleExecuteParams

        if len(distilled_params) == 1:
            event_multiparams, event_params = [], distilled_params[0]
        else:
            event_multiparams, event_params = distilled_params, {}

        for fn in self.dispatch.before_execute:
            elem, event_multiparams, event_params = fn(
                self,
                elem,
                event_multiparams,
                event_params,
                execution_options,
            )

        if event_multiparams:
            distilled_params = list(event_multiparams)
            if event_params:
                raise exc.InvalidRequestError(
                    "Event handler can't return non-empty multiparams "
                    "and params at the same time"
                )
        elif event_params:
            distilled_params = [event_params]
        else:
            distilled_params = []

        return elem, distilled_params, event_multiparams, event_params

    def _execute_clauseelement(
        self,