当我输入时，sudo apt update我得到了这个响应：
Get:1 https://dl.winehq.org/wine-builds/ubuntu bionic InRelease [6,242 B]
Ign:2 http://dl.google.com/linux/chrome/deb stable InRelease
Hit:3 http://dl.google.com/linux/chrome/deb stable Release
Err:1 https://dl.winehq.org/wine-builds/ubuntu bionic InRelease
The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 76F1A20FF987672F
Hit:5 http://ppa.launchpad.net/graphics-drivers/ppa/ubuntu bionic InRelease
Hit:6 http://archive.ubuntu.com/ubuntu bionic InRelease
Hit:7 http://archive.ubuntu.com/ubuntu bionic-updates InRelease
Hit:8 http://archive.ubuntu.com/ubuntu bionic-backports InRelease
Hit:9 http://archive.ubuntu.com/ubuntu bionic-security InRelease
Reading package lists... Done
Building dependency tree
Reading state information... Done
All packages are up to date.
W: An error occurred during …