This PR makes example code and CLI's help message in README.md up to date.
Also, since the library API and CLI's help message can change in future versions,
This PR makes their descriptions in README.md testable so that we can know the need for changes.
This PR makes example code and CLI's help message in README.md up to date. Also, since the library API and CLI's help message can change in future versions, This PR makes their descriptions in README.md testable so that we can know the need for changes.