Shotaro Sano

This issue is still open for contribution. The goal is to remove [this line](https://github.com/optuna/optuna/blob/594858fd3f43fbb713f411a47ff264b08b8d2337/.github/workflows/tests-integration.yml#L63) in the CI setting, after fixing the test failures.

I suspect that the gap between LangChain's MRKL implementation (`zero-shot-react-description`) and what is outlined in the [original MRKL paper](https://arxiv.org/pdf/2205.00445.pdf) is causing some confusion. To elaborate, the original MRKL paper is...