How to use stdin to give data to rankmirrors command

Probably a rooky question, but I have seen that the "rankmirrors" command can use the **stdin** input. But when I run the following command (which retrieve all URL in use in the "mirrorslist" file to the "rankmirrors"), I get an error:

Bash
$ rg -e "^Server" /etc/pacman.d/mirrorlist | rg -oe "https.*"  | rankmirrors -t
Must specify URL, mirrorfile, or stdin.

There is another way to use the previous command **stdout** as current **stdin** of the command ?