package 'python3-pip' has no installation candidate code example

Example 1: pip3 has no installation candidate

// Run
sudo nano /etc/apt/sources.list

// And add these lines.

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

// Press Ctrl+O to save the file. Press Ctrl+X to quit nano. Then run:

sudo apt update
sudo apt install python3-pip

Example 2: E: Unable to locate package python3-pip

sudo add-apt-repository universe
sudo apt-get update