请帮我生成一个代码：宠物网店系统能为人们提供更为便捷、更为满意的宠物服务。宠物网店管理平台是一套专门为宠物店设计的管理软件。该软件结合宠物店的日常管理需求，包括宠物用品销售、宠物美容、宠物医疗、宠物寄养、宠物交易、会员管理等多种业务管理。

以下是一个简单的宠物网店系统代码示例：

class PetStore:
    def __init__(self):
        self.products = []
        self.services = []
        self.members = []
        self.sales = []

    def add_product(self, product):
        self.products.append(product)

    def add_service(self, service):
        self.services.append(service)

    def add_member(self, member):
        self.members.append(member)

    def make_sale(self, sale):
        self.sales.append(sale)

class Product:
    def __init__(self, name, price, quantity):
        self.name = name
        self.price = price
        self.quantity = quantity

    def __str__(self):
        return "{} ({}): ${}".format(self.name, self.quantity, self.price)

class Service:
    def __init__(self, name, price, duration):
        self.name = name
        self.price = price
        self.duration = duration

    def __str__(self):
        return "{} ({} mins): ${}".format(self.name, self.duration, self.price)

class Member:
    def __init__(self, name, email, phone):
        self.name = name
        self.email = email
        self.phone = phone

class Sale:
    def __init__(self, product, service, member):
        self.product = product
        self.service = service
        self.member = member
        self.total_price = product.price + service.price

    def __str__(self):
        return "{} bought {} and received {} for a total of ${}".format(self.member.name, self.product.name, self.service.name, self.total_price)

# Example usage
store = PetStore()

# Add products
food = Product("Pet food", 10.99, 50)
toys = Product("Pet toys", 5.99, 100)
store.add_product(food)
store.add_product(toys)

# Add services
groom = Service("Pet grooming", 35.99, 60)
board = Service("Pet boarding", 25.99, 1440)
store.add_service(groom)
store.add_service(board)

# Add members
john = Member("John", "john@example.com", "555-1234")
jane = Member("Jane", "jane@example.com", "555-5678")
store.add_member(john)
store.add_member(jane)

# Make a sale
sale = Sale(food, groom, john)
store.make_sale(sale)

# Print sales
for s in store.sales:
    print(s)

该代码实现了一个基本的宠物网店系统，其中包括了商品、服务、会员和销售等模块，可以根据需要进行扩展。