Ubuntu execution sudo apt-get update hint missing public key

The following information is indicated:

Get: 1 Http://archive.ubuntukylin.com:10006/ubuntukylin xenial inrelease [3,192 B] Hit: 2 http://mirrors.aliyun.com/ Ubuntu xenial inrelease Ignore: 1 Http://archive.ubuntuk Ylin.com:10006/ubuntukylin xenial Inrelease hit: 3 http://mirrors.aliyun.com /ubuntu xenial-updates inrelease Ignore: 4 http://dl.google.com/linux/ch Rome/deb stable inrelease hit: 5 http://mirrors.aliyun.com/ubuntu                                                              Xenial-backports Inrelease hit: 6 http://dl.google.com/linux/chrome/deb stable Release                                                        Hit: 7 Http://mirrors.aliyun.com/ubuntu xenial-security Inrelease                                            Hit: 9 Http://archive.ubuntu.com/ubuntu xenial Inrelease Downloaded 3,192 B, time consuming 1 seconds (2,616 b/s) is reading the package list ... Complete W:GPG error: Http://archive.ubuntukylin.com:10006/ubuntukylin xenial inrelease: The following signature could not be verified because there is no public key: No_pubkey 8D 5a09dc9b929006w: Warehouse "Http://archive.ubuntukylin.com:10006/ubuntukylin xenial inrelease" does not have a digital signature. N: Data from this source cannot be authenticated, so using it poses a potential risk. N: See the Apt-secure (8) Manual for details about warehouse creation and User configuration.   W: The key for the following ID does not have a public key available: 8d5a09dc9b929006

Workaround:

sudo apt-key adv--keyserver keyserver.ubuntu.com--recv-keys 8d5a09dc9b929006

　　

Ubuntu execution sudo apt-get update hint missing public key