How do i represent an integer in python? [duplicate]

This question already has an answer here:

• Checking whether a variable is an integer or not 35 answers

I am taking in intro CS course and am playing around with some of my old code from an early lab. The program asks for four separate inputs from the user and will then spit out a graph according to the four inputs. I'm trying to get it where if the user does not enter a number then it asks for them to try again and prompt for another input. I've tried things like: (if x != int:) and (if x =\= int:) but nothing has worked for me.