Write definitions for the following two functions using Python: 
 sumN (and) returns the sum of the first n natural numbers. 
 sumN Cubes (and) returns the sum of the cubes of the first n natural numbers. 
 Then use these functions in a program that prompts a user to enter a number ‘n’ and print out the sum of the first n natural numbers, and the sum of the cubes of the first n natural numbers.