Fighting how to deal with a group of knife

Of course it is important to call the police, but a good man is not a good man, in a group of people with knives facing you, self-defense with a steel pipe is a must!

Because the steel pipe is long, I believe that as long as the physical strength is good enough to deal with a group of people with knives or no problem.

As self-defense, you use a steel pipe to hit your opponent's calves! Forearms, and even the head are fine, and hit them until they can't chase you.