input: Write a function to print out all combinations of elements from three lists, where each list contains three elements, in a new line. Each combination should be represented by the elements from the three lists.
  assert combination_printer([1,2,3], [4,5,6], [7,8,9])==None
  # Expected Output:
  # 1 4 7
  # 1 4 8
  # 1 4 9
  # 1 5 7
  # 1 5 8
  # 1 5 9
  # 1 6 7
  # 1 6 8
  # 1 6 9
  # 2 4 7
  # 2 4 8
  # 2 4 9
  # 2 5 7
  # 2 5 8
  # 2 5 9
  # 2 6 7
  # 2 6 8
  # 2 6 9
  # 3 4 7
  # 3 4 8
  # 3 4 9
  # 3 5 7
  # 3 5 8
  # 3 5 9
  # 3 6 7
  # 3 6 8
  # 3 6 9
  assert combination_printer([], [], [])==None
  # Expected Output:
  # (No output)
output: def combination_printer(list1, list2, list3):
      for i in list1:
          for j in list2:
              for k in list3:
                  print(i, j, k)