int score_add(const struct osl_row *row, long score);
int score_update(const struct osl_row *aft_row, long new_score);
int score_delete(const struct osl_row *aft_row);
-int clear_score_table(void);
+void score_clear(void);
bool row_belongs_to_score_table(const struct osl_row *aft_row);
/* attribute */