input: Write a function to print out all combinations of elements from three given lists such that each combination is formed by one element from each list and each combination is printed in a new line. The function should perform this task using nested loops.
  
  def print_combinations(list1, list2, list3):
      for x in list1:
          for y in list2:
              for z in list3:
                  print(x, y, z)
  
  assert print_combinations([1, 2, 3], [4, 5, 6], [7, 8, 9]) == None
output: def print_combinations(list1, list2, list3):
      for x in list1:
          for y in list2:
              for z in list3:
                  print(x, y, z)