checking if input is number pythin code example

Example 1: how to know if a input is a interger in python

whatever = input("Pick an integer > ")
    try:
        whatever_as_an_integer = int(whatever)
        print("That was an integer.")

    except ValueError:
        print("That is not an integer.")

Example 2: how to say that an input needs to be a number python

try:
   val = int(userInput)
except ValueError:
   print("That's not an int!")