sudo(8) add-apt-repository(1) --remove 'deb [arch=amd64] https://packages.elementary.io/appcenter xenial main'
execute a command as another user
Adds a repository into the /etc/apt/sources.list or /etc/apt/sources.list.d or removes an existing one
-r, --remove Remove the specified repository
source manpages: sudoadd-apt-repository