sudo apt install python3-pip

sudo python2 get-pip.py

sudo apt update sudo apt install python2

[server]$ pip3 --version
pip 18.1 from /home/username/opt/python-3.6.2/lib/python3.6/site-packages/pip (python 3.6)

sudo add-apt-repository universe
sudo apt update 
sudo apt install python2
curl https://bootstrap.pypa.io/pip/2.7/get-pip.py --output get-pip.py
sudo python2 get-pip.py