docker installation error

[hariharan382]

HI i am trying to install Docker, but after following few preliminaries, before instalation i tried to update but could not update , I eve purged the installation still i could not get rid of this error

drint@drint:~$ sudo apt-get update

Hit:1 http://ppa.launchpad.net/graphics-drivers/ppa/ubuntu focal InRelease Hit:2 http://in.archive.ubuntu.com/ubuntu focal InRelease
Get:3 http://security.ubuntu.com/ubuntu focal-security InRelease [114 kB]
Ign:4 https://download.docker.com/linux ubuntu InRelease
Hit:5 http://packages.ros.org/ros/ubuntu focal InRelease
Hit:6 https://download.docker.com/linux/ubuntu focal InRelease
Get:7 http://in.archive.ubuntu.com/ubuntu focal-updates InRelease [114 kB]
Err:8 https://download.docker.com/linux ubuntu Release
404 Not Found [IP: 65.8.72.116 443] Hit:9 https://dl.google.com/linux/chrome/deb stable InRelease
Get:10 http://in.archive.ubuntu.com/ubuntu focal-backports InRelease [108 kB]
Reading package lists... Done
E: The repository 'https://download.docker.com/linux ubuntu Release' does not have a Release file. 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.