在不知道正确派生类的情况下创建派生类的实例

class BaseClass:
    def method(self):
        pass

class DerivedClass1(BaseClass):
    def method(self):
        print("This is DerivedClass1")

class DerivedClass2(BaseClass):
    def method(self):
        print("This is DerivedClass2")

class Factory:
    def create_instance(self, condition):
        if condition == 1:
            return DerivedClass1()
        elif condition == 2:
            return DerivedClass2()
        else:
            raise ValueError("Invalid condition")

# 使用工厂类创建对象
factory = Factory()
instance1 = factory.create_instance(1)
instance2 = factory.create_instance(2)

# 调用对象的方法
instance1.method()  # 输出：This is DerivedClass1
instance2.method()  # 输出：This is DerivedClass2