input: Write a function to print out all possible combinations of elements from three given lists, where each combination consists of one element from each list.
  
  def print_combinations(list1, list2, list3):
      for x in list1:
          for y in list2:
              for z in list3:
                  print(x, y, z)
                  
  print_combinations([1, 2, 3], [4, 5, 6], [7, 8, 9])
output: def print_combinations(list1, list2, list3):
      for x in list1:
          for y in list2:
              for z in list3:
                  print(x, y, z)