usage: optuna [-h] [--storage STORAGE] [--storage-class STORAGE_CLASS] [-v | -q]
              [--log-file LOG_FILE] [--debug] [--version]
              {create-study,delete-study,study set-user-attr,study-names,studies,trials,best-trial,best-trials,storage upgrade,ask,tell,help} ...

positional arguments:
  {create-study,delete-study,study set-user-attr,study-names,studies,trials,best-trial,best-trials,storage upgrade,ask,tell,help}
    create-study        Create a new study.
    delete-study        Delete a specified study.
    study set-user-attr
                        Set a user attribute to a study.
    study-names         Get all study names stored in a specified storage
    studies             Show a list of studies.
    trials              Show a list of trials.
    best-trial          Show the best trial.
    best-trials         Show a list of trials located at the Pareto front.
    storage upgrade     Upgrade the schema of an RDB storage.
    ask                 Create a new trial and suggest parameters.
    tell                Finish a trial, which was created by the ask command.
    help                Show help message and exit.

options:
  -h, --help            show this help message and exit
  --storage STORAGE     DB URL. (e.g. sqlite:///example.db) Also can be specified via
                        OPTUNA_STORAGE environment variable.
  --storage-class STORAGE_CLASS
                        Storage class hint (e.g. JournalFileBackend)
  -v, --verbose         Increase verbosity of output. Can be repeated.
  -q, --quiet           Suppress output except warnings and errors.
  --log-file LOG_FILE   Specify a file to log output. Disabled by default.
  --debug               Show tracebacks on errors.
  --version             show program's version number and exit