Hit:1 https://cloud.r-project.org/bin/linux/ubuntu focal-cran40/ InRelease
Hit:2 http://de.archive.ubuntu.com/ubuntu focal InRelease
Hit:3 http://ppa.launchpad.net/deadsnakes/ppa/ubuntu focal InRelease
Hit:4 http://security.ubuntu.com/ubuntu focal-security InRelease
Get:5 http://de.archive.ubuntu.com/ubuntu focal-updates InRelease [114 kB]
Get:6 http://de.archive.ubuntu.com/ubuntu focal-backports InRelease [108 kB]
Fetched 222 kB in 1s (250 kB/s)
Reading package lists...
Error: `.` must contain a package.
Execution halted