TypeError: unsupported operand type(s) for +: 'type' and 'int' code example

Example 1: TypeError: unsupported operand type(s) for +=: 'IntVar' and 'int'

from tkinter import IntVar
X = IntVar()
X.set(X.get() + 1)

Example 2: TypeError: unsupported operand type(s) for +: 'int' and 'str'

do not combine int with string !
Example:int + string = error
correct example: int + int = no error 
                 string + string = no error