Ubuntu 18.04 Depends php7.2-fpm but it is not going to be installed

If you receive the following error when installing the Virtualmin control panel or installing php7.2 on Ubuntu 18.04, the reason is that there are no necessary repository paths in source.List.

nano /etc/apt/source.list
Necessary warehouses are added. Use the commands below.

deb http://archive.ubuntu.com/ubuntu bionic main multiverse restricted universe
deb http://archive.ubuntu.com/ubuntu bionic-security main multiverse restricted universe
deb http://archive.ubuntu.com/ubuntu bionic-updates main multiverse restricted universe

sudo apt update; sudo apt upgrade -y
sudo apt install php7.2-mbstring