我准备更新我的 ubuntu 24.04，在我尝试添加 pgp 密钥之前，一切都正常，经过大量更改后，我尝试将所有设置重置为默认设置，但现在我遇到了 apt 更新问题，我将错误和我的配置粘贴在下面！帮帮我 :|
➜ sources.list.d pwd
/etc/apt/sources.list.d
➜ sources.list.d ll
total 4.0K
-rw-r--r-- 1 root root 343 Dec 17 00:38 ubuntu.sources
➜ sources.list.d cat ubuntu.sources
deb http://archive.ubuntu.com/ubuntu noble main restricted universe multiverse
deb http://archive.ubuntu.com/ubuntu noble-updates main restricted universe multiverse
deb http://archive.ubuntu.com/ubuntu noble-security main restricted universe multiverse
deb http://archive.ubuntu.com/ubuntu noble-backports main universe restricted multiverse
➜ sources.list.d sudo apt update
E: Malformed stanza 1 in source list /etc/apt/sources.list.d/ubuntu.sources (type)
E: The list of sources could not be read.
➜ sources.list.d