input: Write a function that takes a list of numbers from 1 to 8 and prints their cubic values. The function should iterate through each number in the list, calculate its cube, and print the result. The function should be named `print_cubes`.
  
  assert print_cubes([1, 2, 3, 4, 5, 6, 7, 8])==None
  assert print_cubes([5, 2, 7, 8, 3, 4, 6, 1])==None
output: def print_cubes(numbers):
      for num in numbers:
          print(num ** 3)