每当我尝试在 Ubuntu 16.10 中添加存储库时，我都会收到密钥服务器接收失败错误。
例如，在添加 pycharm repo 时，我收到此错误：
sudo add-apt-repository ppa:mystic-mirage/pycharm
The Most Intelligent Python IDE
Enjoy productive Python, Django, and Web development with PyCharm, an intelligent Python IDE offering unique coding experience
This PPA contains both PyCharm Professional and Community Editions
Update 2016-07-22: Unity Menubar Integration enabled. Enjoy!
More info: https://launchpad.net/~mystic-mirage/+archive/ubuntu/pycharm
Press [ENTER] to continue or ctrl-c to cancel adding it
gpg: keybox '/tmp/tmppoqic2l4/pubring.gpg' created
gpg: keyserver receive failed: No keyserver available