这是我收到的错误
Err:7 http://packages.ros.org/ros/ubuntu bionic InRelease
The following signatures were invalid: EXPKEYSIG F42ED6FBAB17C654 Open Robotics <info@osrfoundation.org>
Reading package lists... Done
W: GPG error: http://packages.ros.org/ros/ubuntu bionic InRelease: The following signatures were invalid: EXPKEYSIG F42ED6FBAB17C654 Open Robotics <info@osrfoundation.org>
E: The repository 'http://packages.ros.org/ros/ubuntu bionic InRelease' is not signed.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.
apt ×1