[tiwil]

Simple because you using Debian Linux Distribution, its not work in RHEL or another distro. That's why the tutorial must install phyton in the first.. and you missing something in your command "apt-get"

I don't know what OP's OS, so I decided to put it there. I know he's using CentOS after someone replied again.

And, thanks for your input, I usually use only "apt" instead of full "apt-get", like "sudo apt install package".