从Python中的类对象列表中确认用户和密码

我需要能够验证用户和输入的密码,但是当我运行下面的代码时,我只能验证列表中的第一个元素和第二个元素等没有被验证。

注意:用户和密码作为类对象存储在列表中[如下所示:
admin(user, password)]...

def login(self):
    user_name = input("Please Enter Your Username : ").upper()
    password = input("Please Enter Your Password : ").upper()
    for obj in self.admins:
        while obj.admin_name != user_name and obj.admin_password != password:
            print(" Sorry Username and Password Incorrect Please Re-enter for Validation ")
            user_name = input("Please Enter Your Username : ").upper()
            password = input("Please Enter Your Password : ").upper()
        else:
            print("Greetings,", user_name, "You are Now Logged in the System")
            break