如何在self.__init__中查找属性？

class MyClass:
    def __init__(self, attr1=None, attr2=None):
        self.attr1 = attr1
        self.attr2 = attr2
        
        # 检查是否存在 attr1 属性
        if hasattr(self, 'attr1'):
            print(f"attr1 exists with value: {getattr(self, 'attr1')}")
        else:
            print("attr1 does not exist")
        
        # 检查是否存在 attr3 属性（不存在）
        if hasattr(self, 'attr3'):
            print(f"attr3 exists with value: {getattr(self, 'attr3')}")
        else:
            print("attr3 does not exist")
        
        # 使用 getattr 获取属性值，如果不存在则提供默认值
        attr3_value = getattr(self, 'attr3', 'default_value')
        print(f"attr3 value (or default): {attr3_value}")

# 创建对象并测试
obj = MyClass(attr1="value1")

attr1 exists with value: value1
attr3 does not exist
attr3 value (or default): default_value