public List<String>delNickName(String nickName) throws NickNameNotExist {
		if(!nickNameAlreadyExist(nickName)) throw new NickNameNotExist();
		for (Personne p : listPer) {
			if(p.getListNickName().contains(nickName)) {
				int rang = p.getListNickName().indexOf(nickName);
				p.getListNickName().remove(rang);
				break;
				
			}
		}
		return app.appValid();
	}