input: Write a function to take an integer input from the user and print its cube. The function should prompt the user for a number, calculate its cube, and then print the result.
  assert cube_of_number(3) == "The cube of the number is: 27"
  assert cube_of_number(0) == "The cube of the number is: 0"
  assert cube_of_number(-2) == "The cube of the number is: -8"
output: def cube_of_number(num):
      return f"The cube of the number is: {num**3}"