Example
''' python optimize.py --command 'python train_mnist.py' --params '{'lr': ('lu', 0.001, 0.1), 'momentum': ('u', 0.8, 0.99)}' '''
The executed command must send below texts to interact with optuna
OPTUNA_STEP <step> <intermediate_score>
OPTUNA_FINISHED <final_score>
WARN: As OPTUNA_FINISHED is given, command process is terminated immediately
Users have to finish necessary operations (e.g. model exporting) before printing OPTUNA_FINISHED