$ sudo apt-get update
$ sudo apt-get install python-pytest-instafail 

python-pytest-instafail is installed in your system.

Make ensure the python-pytest-instafail package were installed using the commands given below,

$ sudo dpkg-query -l | grep python-pytest-instafail *

You will get with python-pytest-instafail package name, version, architecture and description in a table

python-pytest-instafail package basic information: