Deepin 15.7 添加Persepolis PPA源失败，提示找不到有效的openPGP数据。
sudo add-apt-repository ppa:persepolis/ppa
Persepolis download manager is a GUI for aria2
website: https://persepolisdm.github.io
github: https://github.com/persepolisdm/persepolis
More info: https://launchpad.net/~persepolis/+archive/ubuntu/ppa
Press [ENTER] to continue or ctrl-c to cancel adding it
gpg: keybox '/tmp/tmp6dqbl2b9/pubring.gpg' created
gpg: /tmp/tmp6dqbl2b9/trustdb.gpg：建立了信任度数据库
gpg: 密钥 AC4E8D9CDCB0980D：公钥“Launchpad PPA for Persepolis Download Manager”已导入
gpg: 合计被处理的数量：1
gpg: 已导入：1
gpg: 找不到有效的 OpenPGP 数据。
解决：
sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys AC4E8D9CDCB0980D
Executing: /tmp/apt-key-gpghome.LApiOjFrpb/gpg.1.sh --keyserver keyserver.ubuntu.com --recv-keys AC4E8D9CDCB0980D
gpg: 密钥 AC4E8D9CDCB0980D：公钥“Launchpad PPA for Persepolis Download Manager”已导入
gpg: 合计被处理的数量：1
gpg: 已导入：1
导入公钥
gpg -a --export B5B7720097BB3B58 | sudo apt-key add -国内有效的kerserver
keyserver.ubuntu.com
pgp.mit.edu
subkeys.pgp.net
www.gpg-keyserver.de
参考文档：
