input: Write a python function to print the keys and values of a dictionary in the given format.
  assert print_dict_items({1: [1], 2: [1, 2], 3: [1, 2, 3]}) == "1 [1]\n2 [1, 2]\n3 [1, 2, 3]\n"
  assert print_dict_items({"a": [10, 20], "b": [30, 40], "c": [50, 60]}) == "a [10, 20]\nb [30, 40]\nc [50, 60]\n"
  assert print_dict_items({}) == ""
output: def print_dict_items(d):
      result = ""
      for key, value in d.items():
          result += f"{key} {value}\n"
      return result