Error with percona repo when running apt-get update

I ran apt-get update on a Ubuntu 12.04 server and this error came up:

Err http://repo.percona.com precise Release

Then I went into the Percona documentation and figure out how to fix it. It's to update the Percona's signing key:

sudo apt-key adv --keyserver keys.gnupg.net --recv-keys 8507EFA5

Then everything works fine again.