error: http://ppa.launchpad.net lucid Release: The following signatures couldn't be verified because

ubuntu 命令行sudo apt-get update

W: GPG error: http://ppa.launchpad.net lucid Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 2EE5793634EF4A35

出现W: GPG 错误：http://ppa.launchpad.net lucid Release: 由于没有公钥，无法验证下列签名： NO_PUBKEY FAF69C646FF368B7的问题，可以在终端中运行：

sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 2EE5793634EF4A35