写一套医药erp软件的代码

由于医药erp软件的功能非常复杂，需要涵盖采购、仓储、销售、财务、统计分析等多个模块，因此这里只提供一个简单的示例代码，仅供参考。

以下是一个简单的药品采购模块的代码：

class PurchaseOrder:
    def __init__(self, order_number, supplier, order_date, delivery_date):
        self.order_number = order_number
        self.supplier = supplier
        self.order_date = order_date
        self.delivery_date = delivery_date
        self.items = []

    def add_item(self, item):
        self.items.append(item)

    def remove_item(self, item):
        self.items.remove(item)

class PurchaseOrderItem:
    def __init__(self, product_code, product_name, quantity, price):
        self.product_code = product_code
        self.product_name = product_name
        self.quantity = quantity
        self.price = price

class PurchaseOrderDAO:
    def save(self, order):
        # 将采购单保存到数据库
        pass

    def load(self, order_number):
        # 从数据库中读取采购单
        pass

class PurchaseOrderService:
    def __init__(self):
        self.dao = PurchaseOrderDAO()

    def create_purchase_order(self, order_number, supplier, order_date, delivery_date):
        order = PurchaseOrder(order_number, supplier, order_date, delivery_date)
        self.dao.save(order)
        return order

    def add_item_to_order(self, order, product_code, product_name, quantity, price):
        item = PurchaseOrderItem(product_code, product_name, quantity, price)
        order.add_item(item)
        self.dao.save(order)

    def remove_item_from_order(self, order, item):
        order.remove_item(item)
        self.dao.save(order)

这个代码示例实现了采购单、采购单条目和采购单DAO，以及采购单服务。该服务允许创建新的采购单，并添加或删除采购单中的商品。我们还可以添加其他模块的代码以实现完整的医药erp软件。