add -f option, refactor generate_sample condition
add -f option, refactor generate_sample condition

takahashim/review,takahashim/review,krororo/review,kuad9/review_study,kmuto/review,orangain/review,kuad9/review_study,masawada/review,kmuto/review,krororo/review,orangain/review,suzuki/review,murashitas/review,krororo/review,suzuki/review,kmuto/review,masawada/review,murashitas/review