Fix - E: Package python3-pip has no installation candidate

# sudo apt-get install python3-pip

Package python3-pip is not available but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source

E: Package 'python3-pip' has no installation candidate

If you are trying to install python3-pip on your Unix-like Operating system (say Ubuntu) and you get the above error, you can fix it by following the below steps,

Step 1: Update apt-get

# sudo apt-get update

Step 2: Upgrade apt-get

# sudo apt-get upgrade

Step 3: Install python3-pip

# sudo apt install python3-pip