input: Write a python function to get the nth item from a list.
  assert get_nth_item([1, 2, 3, 4, 5], 2) == 3
  assert get_nth_item(['a', 'b', 'c', 'd'], 1) == 'b'
  assert get_nth_item([10, 20, 30, 40], 3) == 40
output: def get_nth_item(lst, n):
      return lst[n]