input: Write a python function to swap items in a list.
  assert swap_items([1, 2, 3, 4, 5], 2, 4) == [1, 4, 3, 2, 5]
  assert swap_items(['a', 'b', 'c', 'd'], 'b', 'd') == ['a', 'd', 'c', 'b']
  assert swap_items([10, 20, 30, 40], 20, 30) == [10, 30, 20, 40]
output: def swap_items(lst, item1, item2):
      idx1, idx2 = lst.index(item1), lst.index(item2)
      lst[idx1], lst[idx2] = lst[idx2], lst[idx1]
      return lst