我使用 Software Sources 程序添加了一些额外的存储库。但是当我重新加载包数据库时，出现如下错误：
W：GPG 错误：http : //ppa.launchpad.net trusty InRelease：以下签名无法验证，因为公钥不可用：NO_PUBKEY 8BAF9A6F
apt-key根据官方的 Ubuntu 文档，我知道我可以在终端中修复它。但我希望以图形方式进行。有没有办法在不使用终端的情况下做到这一点？
当我sudo apt-get update收到如下所示的错误时。
W: An error occurred during the signature verification.
The repository is not updated and the previous index files will be used.
GPG error: https://dl.winehq.org/wine-builds/ubuntu bionic InRelease:
The following signatures couldn't be verified
because the public key is not available: NO_PUBKEY 76F1A20FF987672F
W: Failed to fetch https://dl.winehq.org/wine-builds/ubuntu/dists/bionic/InRelease
The following signatures couldn't be verified
because the public key is not available: NO_PUBKEY 76F1A20FF987672F
W: Some index files failed to download. They have been ignored, or old ones …