图书馆管理系统中的图书数量输出问题

在图书馆管理系统中，我们需要对图书的库存数量进行管理和输出。当借出或归还书籍时，库存数量需要及时更新，以便准确反映图书馆的实际库存。以下是一个基于Python语言的简单示例：

# 定义Book类
class Book:
    def __init__(self, title, author, quantity):
        self.title = title
        self.author = author
        self.quantity = quantity
    
    def borrow(self):
        # 借出书籍
        if self.quantity > 0:
            self.quantity -= 1
            return True
        else:
            return False
        
    def return_book(self):
        # 归还书籍
        self.quantity += 1
        
    def __str__(self):
        # 输出书籍信息
        return f"《{self.title}》 ({self.author}) 库存：{self.quantity}"

# 定义图书馆类
class Library:
    def __init__(self):
        self.books = []
        
    def add_book(self, book):
        # 添加书籍到图书馆
        self.books.append(book)
        
    def remove_book(self, book):
        # 从图书馆中移除书籍
        if book in self.books:
            self.books.remove(book)
        
    def search_book(self, title):
        # 查询书籍
        for book in self.books:
            if book.title == title:
                return book
        return None
    
    def list_books(self):
        # 列出所有书籍
        for book in self.books:
            print(book)

# 测试代码
book1 = Book("Python编程基础", "张三", 5)
book2 = Book("数据结构与算法", "李四", 3)

library = Library()
library.add_book(book1)
library.add_book(book2)

print("添加两本书籍：")
library.list_books()

print("借出一本书籍：")
if book1.borrow():
    print("借出《Python编