def level_up
    last_level = @level
    @level += 1
    mhpincrease = $data_classes[@class_id].params[Enums::Param::MAXHP, @level] - $data_classes[@class_id].params[Enums::Param::MAXHP, last_level]
    add_param(Enums::Param::MAXHP, mhpincrease)
    mmpincrease = $data_classes[@class_id].params[Enums::Param::MAXMP, @level] - $data_classes[@class_id].params[Enums::Param::MAXMP, last_level]
    add_param(Enums::Param::MAXMP, mmpincrease)
        $data_classes[@class_id].learnings.each { |learning| learn_skill(learning.skill_id) if learning.level == @level }
        self.points += LEVEL_UP_POINTS
    end

    def level_down
    $data_classes[@class_id].learnings.each { |forgetting| forget_skill(forgetting.skill_id) if forgetting.level == @level }
    last_level = @level
    @level -= 1
    mhpdecr = $data_classes[@class_id].params[Enums::Param::MAXHP, @level] - $data_classes[@class_id].params[Enums::Param::MAXHP, last_level]
    add_param(Enums::Param::MAXHP, mhpdecr)
    mmpdecr = $data_classes[@class_id].params[Enums::Param::MAXMP, @level] - $data_classes[@class_id].params[Enums::Param::MAXMP, last_level]
    add_param(Enums::Param::MAXMP, mmpdecr)
        self.points -= LEVEL_UP_POINTS
    end